NATO's decision to scale back operations with Afghan soldiers and police amid a spike in insider attacks risks undermining the entire international mission in Afghanistan, British lawmakers warned Tuesday.

Following the deaths this year of 51 international troops killed by Afghan forces or militants wearing Afghan uniforms, NATO has said that troops will no longer routinely carry out operations such as patrolling or manning outposts with their Afghan counterparts.

Britain's defense ministry said such operations will now need the approval of a regional commander. It also claimed that NATO's decision was partly in "response to elevated threat levels" following the outrage in Muslim countries over an anti-Islam video that was produced in the United States.

U.K. opposition lawmakers criticized the plan as potentially weakening the wider strategy in Afghanistan.

"This announcement begs more questions than it answers," main opposition Labour Party lawmaker Douglas Alexander told BBC radio.

"Does this represent a temporary tactical response by military commanders on the ground or does it represent a more strategic shift in the mission?" said Alexander, his party's spokesman on foreign affairs.

He said that if a regional commander was "generally unwilling to grant the authority for troops to go out on patrol with Afghan soldiers," the decision risked undermining NATO's plan to train Afghanistan's security forces ahead of the planned withdrawal of foreign troops at the end of 2014.

Denis MacShane, also a Labour lawmaker, said the change appeared to reverse "the whole axis of U.S. and U.K. strategy in Afghanistan" and questioned whether Hammond had been fully involved in discussions.

On Monday, Hammond told lawmakers that insider attacks, including the killing of two British soldiers by a man in Afghan local police officer's uniform on Saturday, would not derail the process of training Afghan security forces so U.K. troops can leave by 2014.

Hammond held talks in Afghanistan last week with President Hamid Karzai on so-called "green on blue" killings, and suggested the only planned change to policy was likely to be more extensive vetting of Afghan forces who work alongside NATO troops.

He was called to make a statement to Britain's Parliament later Tuesday to explain the NATO decision.

"We have said all along we will take every step that we need to take to minimize the risk to our troops and that is what we are doing," Hammond told reporters outside a meeting of Britain's Cabinet and National Security Council

Foreign Secretary William Hague insisted the NATO decision did not represent a major shift in policy, despite the likely changes to the frequency of joint patrols.

"This is not a change in strategy," Hague told Parliament's Foreign Affairs select committee. "The impact of the ISAF announcement will be quite minimal on U.K. operations."

Britain said most of its work advising Afghan security forces would be carried out with entire Kandaks, or battalions -- groups of about 300 to 500 troops. Joint operations involving smaller groups of troops would be "evaluated on a case by case basis," the U.K. defense ministry said.

Since 2008, Britain has suffered 18 deaths in insider attacks, including the weekend killings of two soldiers by an assailant dressed as an Afghan policeman who feigned injury and opened fire as the troops came to his aid.