Islamabad, Pakistan (CNN) -- Gunman opened fire at the base of one of Pakistan's highest peaks, killing 11 people, including 10 tourists and a local guide, sources from the country's foreign ministry said Monday.
The attack took place at the base of Nanga Parbat between midnight and 1 a.m. on Sunday, according to senior police official Ali Sher.
Among the victims were tourists from China, Ukraine and Slovakia, who had come to Pakistan to climb, he said.
"This was not a big hotel, just a small log/hut type lodge, so no major security," Sher said.
Talking about the same attack earlier, authorities had said that gunman burst into a hotel, killing either nine or 10 foreigners.
They said the death toll changed due to difficult communications and the area's remote location.
The victims were: three Ukranians, two Slovakians, two Chinese, one Lithuanian, one Chinese-American, one Nepali, and one Pakistani guide.
"The attackers abducted two local guides and demanded they take them to where some foreigners are staying to carry out the attack," Interior Minister Chaudhry Nisar Ali Khan told parliament on Sunday. "One (guide) was then killed, another escaped and has been detained by police for questioning."
The tourists had no security escort, the minister said.
A spokesman for Tehreek-e-Taliban Pakistan said an affiliated group carried out the attack.
The Pakistan Taliban targeted the foreigners because the international community supports drone strikes, said spokesman Ihsanullah Ihsan.
The attack was also to avenge the killing of Emir Wali-ur-Rehman in a drone strike in Waziristan last month, the spokesman said.
Rehman was the Pakistan Taliban's No. 2 leader.
Pakistani Prime Minister Nawaz Sharif condemned the attack. He ordered an investigation and called for those responsible to be brought to justice.
Saima Mohsin reported from Islamabad; Aliza Kassim reported from Atlanta. CNN's Zahir Shah Sheraz contributed to this report from Peshawar