A suicide bomber who somehow penetrated layers of security blew himself up in the busy lobby of a leading Baghdad hotel on Monday, killing at least 12 people, including a US-allied tribal sheik, police reported. The attack, in which 21 others were wounded, was just one in a surge of five suicide and other bombings Monday that killed at least 32 people across Iraq. In an equally deadly attack, a suicide truck bomber targeted an Iraqi police station shared with US troops in Beiji, 250 kilometers north of Baghdad, killing nine people. Five American soldiers suffered minor wounds, the US command said. The bombing at the high-rise Mansour Hotel, on the west bank of the Tigris River in central Baghdad, struck at about noon as the lobby bustled with members of news media organizations headquartered at the hotel and other guests, witnesses said. A man wearing a belt of explosives walked into the lobby, approached the reception desk and detonated his bomb, police reported. "It was a great breach of security because there are three checkpoints, one outside and two inside," said hotel worker Saif al-Rubaie, 28, who witnessed the blast and said all the casualties were Iraqis, most employees in the reception area. Police said the dead included hotel resident Fassal al-Guood, a Ramadi tribal sheik and former governor of Anbar province who was a leader of the Anbar Salvation Council, which has partnered with US and Iraqi officials to fight al-Qaida influence in Anbar. A noted Iraqi poet, Rahim al-Maliki, also was killed, said Iraqi Media Net, the government organization on whose television network al-Maliki appeared. Reports that al-Guood was a target of the bombing, possibly along with other Salvation Council sheiks, could not be confirmed. The Mansour, which also houses the Chinese Embassy and is the Baghdad home for a number of Iraqi parliament members, is just a kilometer (half-mile) from the heavily fortified International Zone, where the US Embassy and Iraqi government offices are situated. The attack was the fifth in a string of suicide and other bombings Monday morning, from Mosul and Beiji in the north to Hillah in the south. Two were aimed at US targets. Besides nine dead, the truck bombing at the Beiji wounded at least 21 others, police and medical officials reported. American troops share the post with the local police, on the main road in central Beiji, and five US soldiers suffered minor wounds, said Lt. j.g. Karl Lettow, a US command spokesman in Baghdad, who also said the attack involved two vehicle-borne bombs. One wounded man said random gunfire came from the building after the blast. "I was at the grocery market when the explosion occurred and I ran with others to the site to see if there were any casualties and I was shot by fire from police station," said Khalaf Salim, 40. About 45 minutes later, another suicide car bomb exploded at a joint US-Iraqi army checkpoint in central Siniyah, 15 kilometers west of Beiji, killing two Iraqi soldiers and wounding three others, an Iraqi army officer reported. Earlier in the morning, a suicide car bomber struck a checkpoint near the governor's offices in the predominantly Shiite southern city of Hillah, killing at least eight people and wounding 31, police said. It was the second such attack in Hillah in three days. A parked car packed with explosives blew up on Saturday in the center of the city, 95 kilometers south of Baghdad, killing two people. Three of the eight killed in the 6:30 a.m. explosion were policemen, as were at least four of the wounded, said a spokesman for the provincial police department. The attacker drove his car into a checkpoint that leads to the headquarters of the Babil provincial government. Police officer Baha Abdul-Sadda, 21, said he saw a red sedan speeding toward the headquarters, surprising police at the checkpoint and on the building's roof. "The suicide bomber took advantage of the early hour and intended to hit the metal barrier to get inside to hit the building, but the car exploded prematurely at the metal barrier," he said. Abdul-Sadda, who suffered a head injury when thrown against a wall by the blast, spoke from his hospital bed. Hillah, the capital of Babil, has been the target of some of the deadliest car bomb attacks by suspected Sunni Muslim extremists in the four years of insurgency and sectarian killings in Iraq. The fifth bomb was in a parked car that exploded in the center of the northern city of Mosul, killing one civilian and wounding 20 others, police Brig. Mohammed al-Wakaa said. He said there were no police or military targets at the site. In other violence, two mortar rounds Monday morning struck Baghdad's Fadhil district, a Sunni enclave in the central city, killing two civilians and wounding three others, police said. Iraqi police and other authorities often speak only on condition of anonymity, because of concerns over personal security or because they are not authorized to divulge information.