The Free Syrian Army has claimed responsibilty for a series of explosions in central Damascus near the hotel used by the UN observer mission in Syria.Abu Al Noor, a spokesperson for the Ahfad Al Rasoul brigade that is claiming responsibility for the bombing attacks, told Al Jazeera that the FSA had been planning the attacks for a month."The operation was targeting the central security command in response to murders perpetrated by the security forces nationwide,” he said in a phone interview from Damascus on Wednesday morning.Syrian state television reported that the blast, in the Abu Remanih area near a military depot and the trade union headquarters, was caused by a bomb planted in a fuel vehicle on Wednesday morning.Several ambulances rushed to the scene and a security cordon was set up, according to witnesses.Syrian state television reported that the attack wounded at least three people, but the rebels said they suspect many officers had been killed or injured.The FSA planted eight explosive canisters in the vicinity of theSyrian military’s Central Security Command, timed to explode during their daily meeting, Noor said.The FSA had intelligence suggesting some 150 high-ranking officers would be attending the meeting. He did not know how many casualties had occurred because the security forces had secured the area."We will continue to carry out similar operations in the capital until we reach him [Assad] in the presidential palace,” he said.Faisal Mekdad, the Syrian deputy minister, toured the area of the blast shortly after the explosion and said none of the UN staff was hurt. The explosion occurred as UN humanitarian chief Valerie Amos was in the Syrian capital but her team is believed to be staying at a different hotel."This is a criminal act that shows what kind of attacks Syria is being subjected to,” Mekdad told reporters at the scene. "Such explosions will not affect Syria.”"I confirm that we are with the UN and we will do all we can to guarantee their protection so that they carry out their role,” he added.‘Breakthrough’Al Jazeera’s Rula Amin reported from Beirut that FSA’s apparent incursion into the heart of the capital showed they were gaining confidence."If indeed this is the work of the Free Syrian Army, this is a breakthrough for them,” she said. "What’s interesting is that this is a very secure area.” General Babacar Gaye, the head of the UN Supervision Mission in Syria (UNSMIS), held a press conference in the hotel, the Dama Rose, on Monday.Opposition activists said massive explosions echoed across much of the city and a video released by one opposition group showed a large plume of smoke billowing into the sky. The UN mission was not immediately available for comment.