Egypt carried out a second round of airstrikes in eastern Libya Monday, in swift retaliation for the massacre of 21 Egyptian Coptic Christians by Islamic State militants in Libya.
The bombings killed dozens of militants and several civilians in the Islamic State stronghold of Darna, according to Libyan military officials, 1,300 kilometers east of where the executions were reportedly carried out.
Libyan warplanes joined the strikes, which targeted weapons caches and training camps.
Egyptian President Abdel-Fattah el-Sissi had pledged an immediate response in a televised speech, calling the killings an "abhorrent act of terrorism."
"Egypt reserves the right of retaliation, and with the methods and timing it sees fit for retribution from those murderers and criminals who are without the slightest humanity," Sissi said.
Backed by Libya's internationally recognized government, the Libyan air force joined the strikes, which targeted militant weapons caches and training camps.
The rival parliament based in Tripoli, which is supported by some Islamist groups, denounced the airstrikes as a violation of international law and Libyan sovereignty.
Retaliation for beheadings
The air raids began after a video surfaced online Sunday purporting to show the beheadings of the men, who had been taken hostage in Libya in recent months after being separated from their Muslim coworkers.
It remains unclear when the killings occurred.
The militant group's English-language magazine published still images from the grisly scene late last week. It is the largest staged mass killing outside of the Islamic State's base in Syria and Iraq that the militant group has publicized.
In the video, which was reportedly filmed on the Tripoli region coast, the Egyptian men are marched onto the shore wearing orange jumpsuits alongside their executioners, whose faces are covered.
The brutal murders were portrayed in the video as retaliation against what a masked fighter described as “the hostile Egyptian church.” Coptic Christians make up about 10 percent of the Egyptian population and suffer widespread discrimination and persecution.
Egypt has declared a week of national mourning.
"What will be a relief to me is to take a hold of his murderer, tear him apart, eat up his flesh and liver," Bushra Fawzi in Egypt's el-Aour village told the Associated Press, weeping over the death of his 22-year-old son Shenouda.
"I want his body back. If they dumped it in the sea, I want it back. If they set fire to it, I want its dust," Fawzi said.
Militants Threaten Rome
Speaking in English, the only militant dressed differently from his black-clad comrades, wearing a yellow face mask and camouflage, threatens to expand the Islamic State group's reach to Rome, capital of Libya's former colonial overlord and home to the Vatican, as the waves of the Mediterranean lap in the background.
"All crusaders: safety for you will be only wishes, especially when you are fighting us all together. Therefore we will fight you all together,” he tells the camera. "We will conquer Rome by Allah's permission."
The Coptic Church, based in Egypt, is distinct from the Roman Catholic Church and answers to the Pope of Alexandria, Tawadros II.
Shortly before the video of the beheadings was publicized in the Western media on Sunday, Italy announced it had closed its embassy in Libya and recalled its diplomatic staff.
Italian Foreign Minister Paolo Gentiloni said late last week that his country was "ready to fight" in an international coalition against terrorism in Libya.
But Italy's Prime Minister Matteo Renzi is more cautious, telling Italian television TeleGiornale 5, "the situation is difficult, but now is not the time for a military solution." Instead, Renzi backs UN Security Council-led diplomatic efforts in Libya.
International reaction
Libya's internationally recognized government condemned the beheadings, while the Tripoli-based Libyan parliament condemned the Egyptian airstrikes as an aggression on Libyan sovereignty.
Sissi spoke by phone Monday with French President Francois Hollande, whose office said the men discussed the importance of the U.N. Security Council taking new actions to face the danger posed by the Islamic State group.
Arab League Secretary Nabil Elaraby also condemned the killings and threw his support behind Egypt's bombing of Islamic State targets.
“Of course what happened is a barbaric and savage terrorist act that goes back to the Stone Age, and I can't imagine who would do that. Egypt has every right to defend itself and it must take steps against this type of terrorism carried out by those fundamentalists," Elaraby said.
The U.N. Security Council condemned the massacre, saying, "This crime once again demonstrates the brutality of (the Islamic State group), which is responsible for thousands of crimes and abuses against people from all faiths, ethnicities and nationalities, and without regard to any basic value of humanity."
The group also called for accountability in the killings and urged countries to cooperate in bringing the perpetrators to justice.
The United Nations has struggled for months to mediate a resolution to Libya's political chaos, with parallel governments and warring militias struggling for control of the country, leaving a power vacuum and creating an atmosphere of impunity.
The mass killing of the Egyptians comes as Libyans mark the four-year anniversary of the February uprising that led to the ouster and death of former leader Moammar Gadhafi.
In a statement late Sunday, White House Press Secretary Josh Earnest condemned what he called "the despicable and cowardly murder" of the neb, and said the Islamic State's "barbarity knows no bounds."
Accompanied by members of his cabinet, Sissi on Monday visited Egypt's top cathedral to offer condolences to Coptic Pope Tawadros II and the country's Christian community.
Egypt's Coptic Church in a statement called on its followers to have "confidence that their great nation won't rest without retribution for the evil criminals.''
'Barbaric' acts
Al Azhar, the prestigious Cairo-based seat of Islamic learning, said no religion would accept such "barbaric" acts.
Mohamed Ahmed el-Tayeb, Grand Imam of Al Azhar, asked international organizations to counter the violence.
"We feel that this incident has brought us closer and united and from here I call for the free world, the United Nation, the Security Council, the European Union and the Golf Co-operation Council to take an action to stop this brutal ordeal which we haven't seen in the last twenty centuries," el-Tayeb said as he paid condolences to Pope Tawadros II.
Pope Francis, head of the Roman Catholic Church, also expressed outrage over the killings on Monday.
"Their only words were: 'Jesus, help me!' They were killed simply for the fact that they were Christians," Francis said. "The blood of our Christian brothers and sisters is a testimony which cries out be heard. It makes no difference whether they be Catholics, Orthodox, Copts or Protestants... The martyrs belong to all Christians."
Since 2014, the Islamic State group has killed hundreds of civilians in Iraq and Syria and claimed responsibility for the deaths of several foreigners and publicized graphic videos of those killings on social media.
Last month, it released footage of the immolation death of a Jordanian pilot shot down over Syria as well as pictures purporting to show the beheading of two Japanese hostages.
Egypt-Libya relations
Analysts said Libya’s campaign against the Islamic State group has been largely unsuccessful and the militant group has steadily gained ground in the past year. But Egyptian support could turn the tide, they added.
Ziad A. Akl, a senior researcher also at the Al-Ahram Center for Political and Strategic Studies in Egypt, said he thinks the airstrikes could signal that Egypt’s policy against the Islamic State group might be changing.
In the past, he said, Egypt has supported the Libyan military mainly with training.
“I don’t think that they will continue in that manner. I think that Egypt is about to rethink the pattern of its involvement within Libya. The real policy change, I think, is coming," Akl said, adding any possible policy shift is unlikely to mean Egyptian troops on the ground, however.
But Kamel Abdallah, a Libya specialist also at the Al-Ahram Center for Political and Strategic Studies in Egypt, said while Egypt’s army is one of the most powerful in the region, Monday’s attacks were a reaction to the gruesome video released over the weekend, not a change in policy.
Akl and other analysts said Egypt has strong economic and security reasons to fight Islamic State militants in Libya: Millions of Egyptians work in the country, many in the most dangerous parts, even after Libyan authorities stopped issuing visas for Egyptians. Egyptian authorities have also told citizens in Libya to return home.
Heather Murdock contributed to this report from Cairo.