EL-ARISH, Egypt – Egypt vowed Monday to take on Islamist militants who have turned the Sinai peninsula into a lawless haven and are suspected of killing 16 Egyptian troops as the fighters were en route to a failed assault on neighboring Israel.

But the goal of reining in jihadists in Sinai is complicated by limits on military activity in the area under the 1979 peace treaty with Israel and by tensions between Egypt's Islamist President Mohammed Morsi and the country's powerful military.

"The armed forces have been careful in the past months and during the events of the revolution not to shed Egyptian blood," said a statement by the military. "But the group that staged this attack is considered by the armed forces as enemies of the nation who must be dealt with by force."