Gaza-based militants are suspected of carrying out an attack inside Israel Monday from the Sinai Peninsula, the Washington Post reports. The number of militant infiltrations from the Gaza Strip has increased in the year since Egypt's Hosni Mubarak was ousted, and Israeli security officials remain concerned about security cooperation should the Muslim Brotherhood take power in Cairo.

"No doubt Sinai has become a security problem," Israeli vice-premier Shaul Mofaz told Israel army radio. "Today's incident ratchets it up a notch."

One Israeli was killed in the attack and border communities placed in a state of lockdown. Sinai has also suffered from kidnappings of foreign visitors and the 2004-2005 bombing of tourist resorts, a mainstay of the local economy.

Although there was no word on who was responsible, Gaza-based terrorists and al-Qaida's fledgling Sinai branch remain potential culprits. Both have exploited Israel's incomplete border fence with the Sinai, notably in an August 2011 attack that killed eight Israelis and forced a revision of the Jewish state's approach to its formerly peaceful Egyptian border.

The Israeli Air Force struck targets in the Gaza Strip Monday, killing four Islamic Jihad operatives engaged in anti-Israel terror activities. The Israeli army claimed that the strikes were unrelated to Monday's Sinai infiltration attack.