BAGHDAD, Iraq (AP) -- Iraq's vice president escaped an apparent assassination attempt Monday after a bomb exploded where he was making a speech. The blast, in municipal offices, knocked him down and left at least 10 people dead. Adel Abdul-Mahdi suffered bruises in the fall and was hospitalized for medical exams, an aide said. Police initially blamed the attack on a bomb-rigged car, but later said explosives were apparently planted inside the building. The attack sent another message that suspected Sunni militants could strike anywhere despite a major security crackdown across the capital. Meanwhile, Iraqi President Jalal Talabani was being treated at a Jordanian hospital after falling unconscious Sunday. The Iraqi ambassador to Jordan said the 73-year-old leader was stable, and recuperating from exhaustion and pulmonary inflammation. "There's nothing dangerous about his case," Saad al-Hayyani told The Associated Press. The bomb struck while Abdul-Mahdi, a Shiite, was addressing municipal officials in the upscale Mansour district, which has many embassies and saw a rise in private security patrols after past kidnappings blamed on militants. Adbul-Mahdi is one of two vice presidents. The other, Tariq al-Hashemi, is Sunni. At least 10 people were killed and 18 injured in the blast, police said. An earlier blast killed at least three policemen in another area of Baghdad. "The aggression against you this day is further proof that these groups are doing their best to destroy Iraq's unity," said a message to the vice president from Abdul-Aziz al-Hakim, who heads Iraq's largest Shiite political group. Sunday, the leader of a powerful Shiite militia, radical cleric Muqtada al-Sadr, complained bitterly that the U.S.-Iraqi security sweeps around Baghdad have done nothing to stem the bombings that mostly target Shiite civilians. The statement -- read in Baghdad by an aide to al-Sadr -- nearly coincided with a suicide bombing that killed at least 42 people at a mostly Shiite business college. Al-Sadr's sharply worded comments could signal serious strains ahead for the security effort. Al-Sadr's Mahdi Army militia pulled its fighters off the streets under intense government pressure to let the 12-day-old security plan move forward. But a relentless wave of Sunni attacks has apparently tested al-Sadr's patience. A return to the streets by the Mahdi Army forces could effectively kill the security effort and raise the chances of Baghdad falling into sectarian street battles -- the apparent aim of Sunni extremists seeking any way to destroy the U.S.-backed government. "Here we are, watching car bombs continue to explode to harvest thousands of innocent lives from our beloved people in the middle of a security plan controlled by an occupier," said the statement. Al-Sadr, who hasn't been seen publicly in more than a month, led fierce battles with U.S. troops in 2004. But he's allowed the Iraqi political process to move forward to avoid strains with Prime Minister Nouri al-Maliki and the Shiite leadership. The statement, however, was highly critical of the U.S. role in the security plan and urged leaders to "make your own Iraqi (security) plans." He said "no security plan will work" with direct U.S. involvement. Elsewhere, U.S. and Iraqi forces in the Diyala province northeast of Baghdad seized a large weapons cache that includes parts for sophisticated roadside bombs that are believed to originate in Iran.