New Zealand Prime Minister John Key announced Monday that the country will withdraw its troops from Afghanistan earlier in 2013 than planned. He said the move is not prompted by the deaths this month of five New Zealand soldiers, including three who were killed Sunday by a roadside bomb.

August's deaths account for half of all fatalities suffered by the small contingent of New Zealanders in the nine years they have been stationed in central Bamiyan province, which was comparatively stable until a recent upswing in violence.

Key said it was "highly likely" the remaining soldiers from the contingent of 145 would be withdrawn in April 2013. He said discussions for the earlier withdrawal began before the five deaths this month. Murray McCully, New Zealand's foreign affairs minister, had announced in May the troops would be withdrawn "in the latter part of 2013."

Key said he wants to bring home the troops as fast as practicable within a timetable that fits in with the coalition partners.

"We'll do it as fast as we can, and we'll do it in the way that protects our people as best we can," he said.

The U.S.-led NATO forces in Afghanistan plan to end their decade-long combat mission and withdraw almost all troops by the end of 2014. The U.S. this year has been withdrawing a planned 23,000 troops, which would leave 68,000.

Key rejected calls to end New Zealand's role in Afghanistan immediately.

"Yes we need to make it the shortest timeframe we can now logistically, but we have to do it with our partners. If we don't, then the message we send to the rest of all of Afghanistan is that it's time to run for the exits," he said. "And if we do that, then the thousands of people who have lost their lives have been in vain. And I just don't think that reflects the values and principles that underpin New Zealand."

The move is likely to be popular among many New Zealanders, who have increasingly questioned the country's role in the conflict. The New Zealand troops were sent there ostensibly as a reconstruction team, with the mission of helping to rebuild and protect Bamiyan province's infrastructure and social systems. In recent months, however, that role has increasingly given way to combat operations, as violence in the region has increased.

The latest incident on Sunday also marked the first time a New Zealand woman has died in the conflict. Lance Cpl. Jacinda Baker, a 26-year-old medic, was killed in the explosion, as were Cpl. Luke Tamatea, 31, and Pvt. Richard Harris, 21.

According to defense force officials, the three were traveling in a convoy of four Humvees on Sunday to escort a soldier suffering a medical condition back from a visit to the doctor when a roadside bomb exploded, destroying the vehicle and instantly killing the occupants.

Lt. Gen. Rhys Jones, chief of the defense force, said the Taliban have taken responsibility for the attack.

Earlier this month, two New Zealand soldiers were killed and another six injured during a gunbattle with insurgents in the same region.