At least six people were killed and about a dozen wounded in three separate attacks Thursday near Israel’s southern border with Egypt. Armed with guns, explosives and anti-tank missiles, the attackers targeted a passenger bus, an Israeli military patrol and a private car, officials said, adding that a “large number” of assailants were working in multiple groups. The violence comes amid growing concerns over lawlessness and violence in Egypt’s Sinai Peninsula, which borders Israel. Israeli officials said the attack originated in Egypt. Last week, the Egyptian military sent thousands of troops into the area after a spate of attacks on police outposts and an oil pipeline in the Sinai. There is also a growing presence of Islamic radicals there, many of whom flocked to the area after breaking out of prison during Egypt’s revolution that overthrew the government of Hosni Mubarak. Egyptian officials, however, denied that the assailants in Israel came from Egypt.