Britain's David Cameron on surprise visit to Afghanistan

Kabul: Britain's Prime Minister David Cameron on Friday pledged support for Afghanistan's newly sworn-in president and the country's new unity government, saying during a surprise visit to Kabul that Britain is committed to helping Afghans build a more secure and prosperous future.

Cameron was the first of world leaders to meet Ashraf Ghani Ahmadzai, Afghanistan's second elected president. The two had a meeting in Kabul on Friday morning and later held a joint press conference.

"Britain has paid a heavy price for helping to bring stability to this country," Cameron said, paying tribute to the 453 British servicemen and women who died while serving in Afghanistan. "An Afghanistan free from al-Qaida is in our national interest - as well as Afghanistan's ... And now, 13 long years later, Afghanistan can - and must - deliver its own security."

But, "we are not leaving this country alone," he added. "In Britain you will always have a strong partner and a friend."

Cameron arrived a day after visiting British pilots in Cyprus who are taking part in airstrikes on Islamic State group targets in Iraq. British warplanes have been conducting combat missions over Iraq since Saturday, hours after Britain joined the U.S.-led coalition of nations that are launching airstrikes against the extremists.

"The work of defeating Islamist extremist terror goes on elsewhere in the world," Cameron said in Kabul. "And because this threatens us at home, we must continue to play our part."

Cameron was also to visit British troops later Friday.

Ghani Ahmadzai was sworn in on Monday, embarking on a new era for his country with a national unity government poised to confront a resilient Taliban insurgency.

A day later, his administration signed a security agreement allowing for the United States to keep about 9,800 troops in the country to train and assist Afghan national security forces. A separate agreement was signed with NATO, outlining the parameters of 4,000 to 5,000 additional international troops - mostly from Britain, Germany, Italy and Turkey - to stay in a noncombat role after NATO's combat mission ends on Dec. 31.

Former President Hamid Karzai had refused to approve the deal, which is intended to help Afghan security forces combat the insurgency.

The results of the presidential election to replace Karzai took months to resolve, finally coming to a conclusion with the swearing in of Ghani Ahmadzai and the establishment of a national unity government with his former rival for the presidency, Abdullah Abdullah, as the country's new chief executive, a post akin to prime minister.

Cameron lauded both Afghan men, saying they put national interests ahead of "personal power."

"I look forward to working with both of you in the years ahead," Cameron said.

He also added a warning to the insurgents. "If the Taliban want to secure a role in the future of Afghanistan then they must accept that they have to give up violence and engage in the political process," Cameron said.

More than a decade after U.S. forces helped topple the Taliban in the wake of the Sept. 11 attacks, Afghanistan is still at war with the Islamic militant group, which regularly carries out attacks, mainly targeting security forces.

Britain is one of the largest financial donors to the Afghan government and Cameron said he and Ghani Ahmadzai would jointly host a conference on future aid to Afghanistan in November in London.

In addition, Cameron pledged 178 million pounds ($287 million) a year until 2017 to support education, health and other public services in Afghanistan.