ISLAMABAD - Police said Thursday they had arrested an alleged mastermind of an attack that killed 10 foreign trekkers in June at a base camp in the Himalayas.

The June 22 attack was the deadliest assault on foreigners in the nuclear-armed country for a decade and was claimed by a purported new faction of Taliban.

Police in Diamer in the Gilgit-Baltistan region said they had arrested a suspect on suspicion of planning the attack, and an accomplice with whom he allegedly killed three investigating officers.

“The suspects killed the Diamer police chief and two military officers investigating the Nanga Parbat incident,” Mohammad Naveed, a senior police official in Diamer, told AFP by telephone.

The three officials were shot dead last month.

“One of the suspects, Qareeb Ullah, was a member of the Pakistani Taliban and he was involved in planning and executing the killing of tourists at Nanga Parbat base camp,” he added.

Attackers wearing police uniforms stormed the base camp at the foot of Pakistan’s second-highest peak Nanga Parbat.

The victims were identified as one American with dual Chinese citizenship, three Ukrainians, two others from China, two from Slovakia, one from Lithuania and one from Nepal. A Pakistani guide was also killed.

The Taliban said it had set up a new faction, Junood ul-Hifsa, to kill foreigners to avenge US drone strikes on Taliban and Al-Qaeda operatives.

Until the June 22 attack, Gilgit-Baltistan was considered immune from much of the militancy plaguing other areas.

The killings badly affected the local tourism industry, a major economic prop.