Another mass murder by Islamic State appears to have roused Egypt to join the coalition against them - at least, unofficially.

The terrorists brutally beheaded 21 Egyptian Coptic Chirstians in Libya which drew an immediate and decisive response from President Abdel Fattah al-Sisi.

Reuters:

Egypt's air force bombed Islamic State targets inside Libya on Monday, a day after the group released a video showed the beheading of 21 Egyptians there, marking an escalation in Cairo's battle against militants.

It was the first time Egypt confirmed launching air strikes against the group in neighboring Libya, showing President Abdel Fattah al-Sisi is ready to expand his fight against Islamist militancy beyond Egypt's borders.

Egypt said the dawn strike, in which Libya's air force also participated, hit Islamic State camps, training sites and weapons storage areas in Libya, where civil conflict has plunged the country into near anarchy and created havens for militia.

A Libyan air force commander said between 40 to 50 militants were killed in the attack. "There are casualties among individuals, ammunition and the (Islamic State) communication centers," Saqer al-Joroushi told Egyptian state television.

"More air strikes will be carried out today and tomorrow in coordination with Egypt," he said.

The 21 Egyptian Coptic Christians, who had gone to Libya in search of work, were marched to a beach, forced to kneel and then beheaded on video, which was broadcast via a website that supports Islamic State.

Before the killings, one of the militants stood with a knife in his hand and said: "Safety for you crusaders is something you can only wish for."

Egypt's Coptic Christian pope was one of the public figures who backed Sisi when he, as army chief, ousted Islamist president Mohamed Mursi in 2013 after mass protests against him.

The beheadings could pile pressure on Sisi to show he is in control of Egypt's security, even though he has already made progress against Islamist militant insurgents in the Sinai.

Jordan, which had joined the anti-IS coalition, was carrying out limited air strikes until Islamic State executed one of its air force pilots by burning him to death. The execution so  outraged the Jordanian people, that King Abdullah launched massive air strikes against IS targets in Iraq and hinted that Jordan would supply ground troops if the US would take the lead.

Now Islamic State has enraged Egyptians. The response by President al-Sisi could indicate a shift in Egypt's position regarding the anti-IS coalition. Egypt has the largest army in the Arab world and would be needed in any significant ground offensive planned against Islamic State. Al-Sisi will move cautiously. His domestic situation is tenuous. He has terrorists to deal with in Sinai and continuing opposition by supporters of the ousted Muslim Brotherhood.

But most of his political opponents are behind bars - or awaiting execution. And he is hoping that his deployment of crack troops to the Sinai will get the security situation under control. It may be in the near future, he will cast his lot with the coalition - especially if he receives some financial and military inducements from the US.

Obama is not likely to support al-Sisi in any way beyond our current obligations. The president has made it plain that he is kicking the Islamic State can down the road for his successor to handle. But the attacks on IS by Egyptian forces puts them in the same boat as the rest of the coalition when it comes to being targeted by Islamic State. Al-Sisi may eventually find that there is greater safety in numbers and join with his fellow Sunni Arabs in fighting the terrorists.