WASHINGTON (Reuters) - Up to 20,000 U.S. Marines could be deployed in Afghanistan as part of a planned major troop build-up to battle worsening insurgent violence, the top U.S. Marine officer said on Friday.
Marine Corps Commandant Gen. James Conway said any buildup of Marines in Afghanistan would have to be accompanied by an equivalent cut in the 22,000-strong Marine force in Iraq to maintain the corps' schedule of seven-month deployments.
U.S. military planners have proposed injecting up to 30,000 U.S. troops into Afghanistan over the next 12 to 18 months to combat an intensifying insurgency from Taliban militants and other fighters.
The United States now has 34,000 troops in the country, including 2,200 Marines.
But Conway told reporters that sending too many Marines to Afghanistan could jeopardize the corps' ability to resume training in vital areas, including amphibious landings, after a hiatus of several years.
"We hope that the number is 20,000 or less," he said.
"The time is right for Marines in general terms to leave Iraq. It's very much a nation-building kind of environment that's taking place there," he said.
"A building fight taking place in another locale -- that's really where Marines need to be. That's what we offer the nation."
President Barack Obama and his defense advisers are reviewing options for how quickly to reduce the U.S. force in Iraq, which currently stands at 143,000 troops.
Marines would likely be deployed to southern Afghanistan where NATO commanders say there are not enough troops to combat growing Taliban influence in the countryside.
Conway said the expected Marine deployment to Afghanistan would include at least one squadron of tilt-rotor MV22 Osprey aircraft, the half-airplane half-helicopter made by Textron Inc. and Boeing Co..
"It's made for a place like Afghanistan," he said, adding that the Marines and U.S. special forces were installing a belly gun to the Osprey to make it more effective against insurgents in Afghanistan.
He said the Marines are also working to modify the blast-resistant vehicles designed to protect troops from roadside bombs.
The marine-resistant ambush-protected trucks, or MRAPs, have not performed well off-road and Conway said the Marines would test a new version in the barren Afghan landscape that uses independent suspension instead of a heavy axle.
"The initial tests have been somewhat encouraging," Conway said. "We're looking at how rapidly we can prove the product before doing a massive overhaul of vehicles we've got and get them to Afghanistan."
He added that the Marine Corps has no plans to buy more vehicles.
Reporting by David Morgan; Editing by Xavier Briand