In what appears to be a gathering battle, Egyptian officials said Thursday that Islamic State (ISIS) terrorists in Libya have kidnapped ten Egyptian nationals.

The kidnappings took place in Tripoli, where fighting between ISIS, the Libyan government, and other rebel groups is taking place.

The Egyptian Foreign Ministry said that it had received word of the kidnappings earlier Thursday. They had no information on the identities of the victims, and ISIS has not commented on the report.

On Sunday, Egypt offered to evacuate the thousands of its citizens who are in Libya when ISIS beheaded 21 Coptic Christians last week. In response to those beheadings, Egyptian fighter jets on Monday bombed ISIS targets in Libya, the first time Egypt has admitted doing so.

Between 40 and 50 ISIS men were killed in the joint attacks by the Egyptian and Libyan militaries, according to Saker al-Jarushi, a commander in Libya’s air force quoted by Reuters. He added that weapons and communications centers were also hit.

If the reports were true, it was likely, sources in Egypt said, that ISIS had staged the kidnappings in retaliation for that attack. Egypt will now have to develop a retaliation for that attack, the sources said, and it was possible that the retaliation would be greater than the attack on Monday, in an attempt to break what could turn into a degenerative pattern of action on both sides that could lead to all-out war.

The report of the kidnapping comes a day after Italian officials expressed serious concerns that they could face an invasion by Islamic State forces, In a video of the executions Sunday, a masked ISIS terrorist threatens the group’s next move, saying that ISIS “will conquer Rome, by Allah’s permission, the promise of our prophet, peace be upon him.”

In an interview with the Associated Press, Italian Defense Minister Roberta Pinotti said that Italy was prepared to contribute as many as 5,000 troops on a mission to liberate Libya from ISIS, if Western states were to decide to undertake such a mission.

However, he said, Rome was willing to wait until the UN Security Council decided on collective action. The issue of the ISIS incursion into Libya is now under discussion by the Council.