Speaking to reporters in Kabul Saturday morning U.S. Senator John McCain said NATO's European members need to accept responsibility for combat operations in the war-torn country.
"Its very important that the other countries represented here remove their national caveats which restraint the ability of their military to perform and makes it extremely difficult for our NATO commanders to call on them for assistance when needed in combat zones, especially in the south," added McCain.
NATO currently has about 32,000 troops in Afghanistan but a number of countries, including France and Germany have resisted efforts to deploy their national troops to combat areas.
Senator McCain said that sort of stipulation "makes it very difficult to work as a team."
He also urged European countries to provide additional funds to help fight Afghanistan's massive illegal opium industry. According to a recent U.N. survey, Afghanistan currently produces about 90 percent of the world's opium supply and many of the profits help fund the Taleban insurgency.
McCain spoke from inside the heavily fortified U.S. military base in central Kabul.
If necessary, he said, the United States would consider sending additional troops to the country but, for now, the emphasis is on training the Afghan National Army.
His comments come as pro-Taleban insurgents continue to destabilize vast portions of the war torn country, particularly in the south and east.
Both U.S. and Afghan officials say many of the attacks have originated from across the border inside Pakistan's tribal areas.
McCain sharply criticized a controversial peace deal Pakistan recently signed with tribal militants near the Afghan border.
"We don't like it. The attacks from that area have increased, and we think that unless there is some dramatic change, that we will continue to see those increases," he added.
McCain is scheduled to visit Pakistan late Saturday and is expected to discuss regional security issues with local officials.