Two rockets were fired from southern Lebanon into Israel Friday, prompting Israel to respond with artillery fire, Lebanese security and military officials said. The exchange, in which no casualties were reported by either side, was the latest in persisting tensions between the two archenemies. It was the fourth time rockets have been fired from Lebanon into Israel, each time bringing Israeli retaliation. It was not immediately known who fired the rockets Friday. But radical Palestinian factions in Lebanon have been blamed in the previous barrages this year. The Israeli military said it “views this incident very severely and we hold the government of Lebanon responsible.”The US strongly condemned the rocket attack. “We strongly condemn these attacks which were in clear violation of the cessation of hostilities called for in UNSC (UN Security Council) resolution 1701,” said PJ Crowley, US State Department spokesman. He said the incident “highlights the urgent need to put arms in Lebanon under control of the state and the need for the international community to remain fully committed on supporting UNIFIL which is the UN mission in Lebanon.”