By Jessica Donati and Rob Taylor KABUL (Reuters) - NATO ordered a cutback on Tuesday on operations with Afghan forces in response to a surge of so-called insider attacks on foreign servicemen, but said the restriction was temporary and would not derail a 2014 handover of security to Afghan forces. The order indefinitely suspending most mentoring operations was issued by the second most senior U.S. commander in Afghanistan, Lieutenant-General James Terry, and applies to all front-line missions involving units smaller than an 800-strong battalion. But a senior NATO spokesman, U.S. Colonel Tom Collins, said the order was only a "temporary and prudent response" to current threats of insider attacks and a week of mounting anger across the Muslim world over a film mocking the Prophet Mohammad. "It will apply only until the threat level returns to a tolerable level," Collins said, adding that separate training missions would be unaffected and the scaling back would apply only to smaller front-line and field troops. Enabling missions, like NATO helicopter support for Afghan troops and medical evacuations by air, would also be unaffected, Collins told Reuters. But even a limited cutback is a major turnaround for NATO's core mission of a strong training role for the 350,000 members of the Afghan security forces who will now have to cope with reduced support from the 100,000-strong NATO-led force backing the Afghan government against Taliban insurgents. At least 51 members of the NATO force have been killed in insider attacks this year, in which Afghan police or soldiers have turned their weapons on their Western mentors. That represents a spike of more than 40 percent on similar incidents for the whole of last year. The order, which appeared to take several coalition members including Britain and Australia by surprise, was issued after weekend attacks by Afghan police in which six foreign soldiers were killed in the south, where the Taliban draw most support. Australian troops, based in the southern province of Uruzgan, were seeking urgent clarification on how the change would be applied, while British Defence Secretary Philip Hammond did not mention the shift in parliament on Monday. But Britain's Foreign Secretary William Hague told a parliamentary committee in London on Tuesday that the strategy ahead of the 2014 pullout of most Western combat troops was unaltered. The impact on UK operations will be minimal. It doesn't mean the way UK troops conduct operations ... is going to change. It does require the chain of command to be consulted in a different way," Hague said. NATO commanders said that meant smaller joint operations could still be approved, but on a case-by-case basis in which junior commanders would have to set out measures to reduce the risk of attack by rogue Afghan soldiers or police. U.S. Defense Secretary Leon Panetta told a news conference in Beijing on Tuesday the U.S. government was concerned about the insider attacks but the plan to hand over security to Afghan control by 2014 remained in place. That underscored a scramble among coalition countries to contain the damage caused by insider attacks both on front-line troop morale and on fading support at home for the 11-year war. "We haven't heard officially from foreign forces about it," Afzal Aman, head of operations for the Afghan defence department, told Reuters. The Pentagon said in a statement the decision was reached with key Afghan leaders. The order to curtail joint operations would hobble support from NATO for Afghan military operations at a time when the Taliban were stepping up attacks, Aman said, including a raid on a major foreign force base in Helmand on Friday which destroyed more than $200 million worth of Harrier fighter jets. The order still allows major joint operations above battalion size to take place, but these are less frequently conducted than smaller platoon and squad-size missions mounted against small insurgent groups. The scaling back of cooperation could also complicate tense negotiations between Washington and Kabul on a deal to keep some special forces and trainers in the country after 2014, a sensitive topic for Afghans embittered by continued civilian deaths and more than a decade of war. Karzai's office also denounced a NATO weekend air strike in which at least eight women collecting firewood were killed east of the capital. Additional reporting by Mirwais Harooni in KABUL, Peter Griffiths and Maria Golovnina in LONDON and David Alexander in BEIJING; Writing by Rob Taylor; Editing by Robert Birsel