The Egyptian foreign ministry has condemned the beheading of British hostage David Haines, who was kidnapped by ISIS militants in Syria last year.
"This was a barbaric and terrible act that is totally incompatible with the teachings of the Islamic religion," the statement said.
Foreign ministry spokesperson Badr Abdel-Ati stressed the importance of international cooperation to combat terrorism.
On Saturday, US Secretary of State John Kerry met with Egypt`s president Abdel-Fattah El-Sisi to discuss plans for an international anti-terrorism coalition.
Haines is the third Westerner beheaded in recent weeks by ISIS, which has seized wide swaths of territory in Syria and Iraq.
The group killed a US journalist, James Foley, last month, before it beheaded another journalist, Steven Sotloff, earlier this month.