MOGADISHU, Nov. 9 -- At least 15 people were killed in triple bomb blasts that rocked Somalia's capital Mogadishu on Friday, police and witnesses said.

The first blast hit Sahafi Hotel while the other two occurred near the hotel opposite the Criminal Investigations Department headquarters.

A police officer who did not want to be named told Xinhua that the victims include passengers on public service vehicles.

"We know many people were killed but for now we have established those who died are 15," the officer said, adding the death toll could rise.

Hassan Yusuf, a witness, told Xinhua the blasts shook the whole area as people scampered for safety and plumes of white smoke could be seen billowing into the air amid sustained gunfire.

"There were massive blasts and everyone was running for their lives," Yusuf said.

The militant group al-Shabab has claimed responsibility for the latest attack.

The police officer said four of the attackers who wanted to enter Hotel Sahafi were killed by security forces; there were reports that a former government official was among the wounded.

"Al-Shabab fighters tried to enter Hotel Sahafi but were shot by security forces," said one of the witnesses who refused to be named.

Insurgents have stepped up their assaults against the government troops and the African Union Mission in Somalia across the southern and central parts of the Horn of Africa nation.