Kabul, Afghanistan (CNN) -- Afghanistan is the most important foreign policy and national security issue facing Britain, Prime Minister David Cameron said Thursday while on an unannounced visit to Kabul.
After meeting with Afghan President Hamid Karzai, Cameron said 2010 is the "vital year" for Afghanistan, when coalition forces must make progress in driving out al Qaeda and handing security back to local forces.
Cameron pledged an extra 67 million pounds (about $98 million) to counter the threat from improvised explosive devices, commonly used as roadside bombs. The money will in part be used to double the number of British teams sent to deal with the devices, he said.
"I think there is progress being made," he said. "Our overriding focus must be to help the Afghans and to help Afghanistan to take control of its own security and its own destiny."
Security concerns forced Cameron to change his own schedule in Afghanistan Thursday.
He was traveling by helicopter in Helmand province, a stronghold of the Taliban, when British commanders altered his route because of "the operational situation" in the area, a British military source said.
Cameron was not attacked and his party was never under direct threat, the source said.
The British official asked not be identified talking about sensitive intelligence matters regarding the prime minister's personal security.
Britain supports the U.S. strategy of increasing the level of military commitment in Afghanistan this year and coupling it with a "political surge."
"We're only six months into that process, and we want to be driven by the results of that process," Cameron said.
He also promised more frequent updates on the British effort in Afghanistan, including quarterly statements in the House of Commons and regular public information, "so people can see progress."
The Afghanistan visit marks Cameron's first trip outside Europe since becoming prime minister.
CNN's Barbara Starr, Thomas Evans and Laura Perez Maestro contributed to this report.