Egypt's Interior Ministry says gunmen have opened fire on a security convoy in central Sinai, killing a police lieutenant and seriously injuring another policeman before fleeing.

The ministry said in a statement on its official webpage that a patrol in the Nekhel area in the center of the desert peninsula was attacked by an unknown number of gunmen Tuesday.

It described them as "criminal" but gave no other details.

The government has promised to restore order to Sinai, where lawlessness and arms smuggling have increased since the ouster of longtime ruler Hosni Mubarak in February 2011.

Tribes and gangs are involved in armed robberies and the kidnapping of tourists to negotiate demands with the government, while Islamist militants frequently attack the police and military.