MOGADISHU, Somalia — At least six people were killed and many more were wounded after consecutive car bombings and an attack by armed militants at a hotel in Mogadishu on Wednesday evening, officials said.

A vehicle loaded with explosives crashed into a police car outside the gate of the Jazeera hotel and exploded. That was followed, the authorities said, by another blast in the middle of the rescue operation. Then, gunmen rushed toward the hotel and a firefight broke out between them and the police, according to Gen. Abdihakin Dahir Saacid, the police chief. He told the state news media that the police had foiled the raid.

"The first suicide car bomber hit at the back of a police car at the gate of the Jazeera hotel," General Saacid said. "Another car loaded with explosives blew up during the rescue operation and the terrorist fighters trying to enter the hotel were killed on the spot."

The scene was sealed off soon after the attack. The authorities said that at least six people had been killed, though police sources said that number was likely to rise. Hospital sources said that at least 10 people had died.

No group claimed responsibility for the attacks, despite threatening messages from the Islamist militant group Shabab broadcast on local radio stations in the previous 24 hours. The messages warned of attacks on government installations in Mogadishu on Dec. 31 and told civilians to stay away.

The hotel, which is near Mogadishu's airport, has long been favored by foreign visitors, and government officials frequently gather there.

In September 2012, three suicide bombers tried to assassinate Hassan Sheik Mohamud, Somalia's newly elected president, as he was holding a news conference at the hotel with the visiting Kenyan foreign minister. Mr. Mohamud was not harmed, but an African Union soldier was killed.

The bombs on Wednesday night went off as Somalis were still celebrating the New Year and after the prime minister, Abdiweli Sheikh Ahmed, visited the Defense Ministry and a military training camp, vowing that his government would bolster security.