The death toll from a brazen suicide attack at a luxury hotel in northwestern Pakistan late Tuesday has risen to 15, with two United Nations relief workers among those killed.

Rescuers search for victims of a suicide blast at Peshawar's Pearl Continental Hotel, 09 Jun 2009At least 70 other people were wounded when attackers detonated a truck bomb outside the Pearl Continental Hotel in Peshawar, the capital of Pakistan's North West Frontier Province.

Provincial politicians, as well as U.N. personnel, were inside the hotel at the time of the blast.

The U.N. confirms at least two of its foreign staffers are among the dead. They are identified as Aleksandar Vorkapic, a Serbian national working for the U.N. refugee agency and Perseveranda So, a Philippine national working for the U.N. children's agency.

Pakistani President Asif Ali Zardari and Prime Minister Yousuf Raza Gilani denounced the attack and reiterated Islamabad's commitment in the fight against terrorism.

U.N. Secretary-General Ban Ki-moon also condemned the violence as a "heinous terrorist attack which no cause can justify."

Witnesses say the attackers shot their way past guards and set off a massive blast that ripped through the hotel's side, setting the building on fire. 

No one claimed responsibility for the bombing. But Aftab Sherpao, whohas served as both provincial chief minister and interior minister,said the attack was clearly designed to pressure the government as itfights Taliban insurgents in the region's Swat Valley.

Pakistani authorities say more than 1,300 militants and about 100 soldiers have been killed since the offensive began in late April.