KABUL: The U.S. military has suspended training of some Afghan forces while the Americans review the process of vetting new recruits following a spike in deadly attacks on international troops last month, officials said Sunday.

There have been 34 attacks by Afghan police or soldiers on their international allies so far this year – at least 12 in August alone. The members of the Afghan security forces have killed 45 international troops, putting intense strain on the relationship.

The attacks have complicated a key pillar in the plan for the U.S.-led coalition to withdraw by the end of 2014 – training Afghan forces to take the lead in securing their own country.

Lt. Col. Todd Harrell, a spokesman for U.S. special operations forces in Afghanistan, said the Americans have halted training for at least a month of about 1,000 trainees of the Afghan Local Police, a government-backed militia that is under the authority of the national police but operates independently. He said the Americans are redoing background checks on the Afghans.

“The training of the ALP recruits has been paused while we go through this re-vetting process to take a look at this process to see if there’s anything that we can improve,” Harrell said. “It may take a month. It may take two months. We don’t know.”

The United States and its allies have been training the Afghan army and police so that they can gradually take over security for the country by the end 2014. They hope to have about 350,000 Afghans trained and ready by the end of the year.

Coalition authorities have said about 25 percent of this year’s insider attacks had confirmed or suspected links to the Taliban. The militants have sometimes infiltrated the ranks of the Afghan army and police and in other cases are believed to have coerced or otherwise persuaded legitimate members to turn on their coalition partners.

The international forces in Afghanistan have been revisiting both security for their forces and re-examining the backgrounds of the Afghan forces in the wake of the recent attacks on international troops. The coalition has already been re-vetting Afghan soldiers returning from leave.

U.S. special operations forces are responsible for the 16,000-strong ALP and decided to stop training the new recruits among them while re-vetting them. The ALP already in the field, having been trained, will continue to operate as normal, Harrel said. The government will also keep recruiting new members, he said.

Col. Tom Collins, a spokesman for the international military coalition in Afghanistan, also said there was no set date to resume training of the ALP.

The pause in training was first reported by the Washington Post.

Harrell disclosed for the first time Sunday that the Americans last month suspended operations by the Afghan special forces to re-vet those soldiers for any potential ties to insurgents or any other indications that they might turn on their allies. He said the suspension lasted less than two weeks and the forces have since resumed operations.

The Post also reported that training of special operations forces had been halted. But a spokesman for the NATO training mission in Afghanistan, or NTM-A, which oversees this training, said there has been no such pause.

“There has been no halt in training with NTM-A assets as they relate to special forces,” said Maj. Steve Neta of the Canadian military. He also said no other training programs involving the traditional military or police have been halted for re-vetting.

The head of the Afghan special operations forces, Brig. Gen. Sayed Abul Karim, confirmed there has been no pause to the training of his forces. The program to train Afghan special operations forces had already been on break for the Muslim holy month of Ramadan, and had been scheduled to restart in mid-September.

“It will continue,” he said, adding it has not been halted. “After Sept. 15, we restart.”