Afghan authorities have arrested a man who served as a translator for U.S. Special Forces and was wanted on allegations he tortured and killed civilians, the country's intelligence service said Monday.

Zakaria Kandahari was picked up "recently" in the southern city of Kandahar for "various crimes," in a special operation conducted by the Afghan National Directorate for Security, the intelligence agency said in a statement.

It did not elaborate, but the Defense Ministry has said Kandahari was wanted on charges of murder and torture in connection with the disappearances of nine boys and men who turned up dead.

The U.S.-led coalition has denied any involvement in the disappearances, but the case has further strained Washington's relations with President Hamid Karzai, and could complicate plans to leave special operations forces in Afghanistan after combat troops complete their withdrawal next year. American officials have suggested keeping a special operations presence in Afghanistan in a counter-terrorism role against al-Qaida even after all other combat troops leave at the end of 2014.

When the allegations about Kandahari surfaced, Karzai ordered U.S. special forces out of the Narkh district of Wardak province, where the disappearances occurred. Karzai had originally ordered them out of the whole province but Gen. Joseph Dunford, the top U.S. commander in Afghanistan, said such a move would threaten the security of Kabul, 45 kilometers (less than 30 miles) south.

When he was arrested, Kandahari had three pistols, two fake Afghan National ID cards and seven other false IDs on him, the intelligence service said.

It added that it would release further details about the case later, and that its investigation of Kandahari is ongoing.