A suicide bomb attack on a luxury hotel in the north-west Pakistani city of Peshawar, has killed 15 people and injured at least 60, BBC reported.
Gunmen stormed the outer security barrier at the Pearl Continental Hotel before blowing up a vehicle containing, police say, 500kg of explosives.
Two foreign citizens - both UN workers - were killed and several were injured.
A series of bombs have hit cities, including Peshawar, since a government crackdown on Taliban militants.
Peshawar, the main city in the country's north-west, is not far from the Swat valley, where the government offensive has been concentrated.
Pakistani Prime Minister Yusuf Raza Gilani swiftly condemned the attack but the blast hardly comes as a surprise, says the BBC's Chris Morris, in Islamabad.
While there was no immediate claim of responsibility for Tuesday night's attack on what is the most prominent hotel in Peshawar, our correspondent says most people will assume it to be the work of the Taliban.
A symbol of Peshawar's contact with the rest of the world, a place where government officials and foreign dignitaries are accustomed to staying, has been attacked, he adds.
The attack killed a Serbian UN refugee agency worker and a Unicef worker from the Philippines.
The injured include a British man and a German national, Peshawar district coordination officer Sahibzada Anis said.
At least a dozen UN employees were staying at the hotel at the time of the explosion.
UN Secretary-General Ban Ki-moon spoke of "a heinous terrorist attack which no cause can justify".
'Shouting and running'
Eyewitnesses told the BBC News website the blast could be seen up to 5km (3 miles) away. The blast left a large crater and parts of the hotel were destroyed.
Three men riding in a truck approached the main gate of the hotel and opened fire at security guards before driving inside, police official Liaqat Ali told AP, quoting witness accounts.
"They drove the vehicle inside the hotel gates and blew it up on reaching close to the hotel building," he added. Ali Khan, a hotel waiter, said he had been working when the attack happened.
"I was in the Chinese restaurant when we heard firing and then a blast," he told Reuters news agency. "It was totally dark and people started shouting and running."
An injured man, Jawad Chaudhry, said he had been in his room on the ground floor when he heard gunshots, then a big bang.
"The floor under my feet shook," he said. "I thought the roof was falling on me. I ran out. I saw everybody running in panic. There was blood and pieces of glass everywhere."
Musa Khan, a BBC News website reader in Peshawar, said he was far away when the blast happened but could tell it was "huge".
"I was in the university lawn with my friends," he said. "I saw the red light from there blowing and then I heard a huge sound."
Another Peshawar reader, Imran, said window panes 5km away had been shattered while a third, Samee Uddin, reported gunshots and then a "huge cloud of smoke [which] could be seen from more than 3km away".