An Israeli air strike killed two Palestinians in the Gaza Strip on Tuesday, June 19 near the border with Israel and the enclave's ruling Hamas movement fired rockets across the frontier for the first time in more than a year, Reuters said.

Palestinian medical officials said the two men were civilians. The Israeli military said aircraft "targeted a terrorist squad identified handling an explosive device" in the central Gaza Strip near Israel's border fence.

The Islamist Hamas group said its Izz el-Deen al-Qassam brigades fired four rockets into Israel in response. No casualties were reported.

Although other militant groups have launched rockets across the border in previous surges of violence, Hamas had held its fire under unofficial truces with Israel.

On Monday, Israeli air strikes killed four Palestinian militants in the enclave, attacks which Fawzi Barhoum, a Hamas spokesman, said moved the group's military wing "to take a firm stance" and launch rockets.

Hours before the aircraft went into action on Monday, militants who crossed into Israel from Egypt's Sinai desert fired on Israelis building a barrier on that frontier, killing one worker, before soldiers shot dead two of the attackers.

The Sinai attack, launched soon after the Muslim Brotherhood declared victory in Egypt's presidential election, raised Israeli concerns about lawlessness in the area since the fall of president Hosni Mubarak last year.