Syria Blames Rebels for Blast That Killed 16 Syrian state media said Thursday that anti-regime bomb-makers accidentally set off blasts a day earlier that flattened parts of a residential area in the central city of Hama and killed at least 16 people. Syrian activists gave a different account, however, and blamed intense shelling by the regime. It was impossible to independently verify the conflicting accounts because President Bashar Assad's regime, facing a 13-month-old uprising, has restricted access for journalists and other outside witnesses. As the violence in Syria continues despite U.N.-led efforts to implement a cease-fire, the international community is becoming increasingly impatient with the Assad regime. On Wednesday, France raised the prospect of military intervention in Syria, saying the U.N. should consider harsher measures if a peace plan by special envoy Kofi Annan fails. A prominent activist urged U.N. observers to investigate the blast. A pair of U.N. observers is stationed in Hama, part of an advance team of 15 that is to be beefed up in coming weeks to up to 300. Amateur videos said to be of Wednesday's incident in Hama showed a large cloud of white and yellow smoke rising from a neighborhood surrounded by green fields. In a later video, dozens of people are searching the debris, including huge chunks of cement and broken cinderblocks. Another clip shows the bloodied body of a little girl being carried through a crowd of wailing men. In this photo released by the Syrian official news agency SANA, Syrian honor guard soldiers carry the coffins of Syrian army soldiers who were killed in recent violence in the country, during their funeral procession at the military hospital in Damascus, Syria, Tuesday April 24, 2012. President Bashar Assad's enemies are resorting to a new tactic to chip away at the regime targeted killings. In recent weeks, gunmen have shot dead a number of military officers in a surprisingly brazen escalation that suggests a coordinated and increasingly sophisticated approach. In the latest such attack, two intelligence officers are killed in the capital and an army truck was booby-trapped. The state-run Syrian news agency SANA said rebel bomb-makers mishandling explosives set off a blast that killed at least 16 people and severely damaged at least six houses. The Local Coordination Committees, a network of activists, said the destruction was caused by intense shelling from tanks on the areas. "The area was shelled for a long period," said spokesman Omar Idlibi, denying the blast was triggered accidentally by rebels. A second group, the Britain-based Syrian Observatory for Human Rights, said the cause of the destruction was not immediately clear. The Observatory initially cited reports by local residents that they had come under shelling attack from regime forces. However, the head of the group, Rami Abdul-Rahman, said he cannot be sure those reports are accurate. Abdul-Rahman called for an investigation by U.N. observers. French Foreign Minister Alain Juppe said Wednesday that France had discussed invoking Chapter 7 of the U.N. Charter, which can be enforced militarily, with other world powers. For now, the international community remains united in support of Annan's plan, which calls for a cease-fire, to be followed by talks between the regime and the opposition on a political solution to the conflict that has killed more than 9,000 people.