TheUnited Stateson Monday denounced the deadly attack onEgyptian border guards in Sinai, pledging assistance to the Egyptian government.

"We condemn in the strongest terms yesterday's deadly terrorist attack against Egyptian border guards in Sinai and againstIsrael, " State Department spokesman Patrick Ventrell said.

"We support the Egyptian government's pledge to bring the perpetrators to justice and to take measures to strengthen security in the Sinai," he told reporters at a regular news briefing.

Masked gunmen attacked the border guards on Sunday immediately after sunset prayer, leaving 15 dead and seven others seriously injured.

Security has deteriorated in Sinai since Egypt was plunged into turmoil early last year.

"The security situation in Sinai is something that we've raised with Egyptian authorities, it's something that has been a matter of ongoing concern, and we stand ready to assist the government of Egypt as it acts on President (Mohamed)Morsi's pledge to secure the Sinai and address the threats of violent extremism and border security," Ventrell said.