Barack Obama has told US forces on his first visit to Afghanistan as US president that they are there to help Afghans to forge a "hard-won peace".

奥巴马就职总统以来首次出访阿富汗，他向美国军队发表演讲，称他们是在帮助阿富汗人民共建一个“来之不易的和平”。

President Obama: "There is no visit I consider more important than this one"

Addressing soldiers and civilians¹ at Bagram air base near Kabul, he thanked them for their service and said they would prevail against（压倒，胜过） their enemies.

They were there, he said, to "keep America safe and secure".

On a trip lasting² just a few hours, he met Afghan President Hamid Karzai and invited him to the US in May for talks.

The US president said he wanted to see progress continue on Afghan efforts to tackle corruption³ and drug-trafficking.

In December, he ordered the deployment⁴ of an extra 30,000 US troops to Afghanistan.

Only a few thousand of the extra forces have arrived so far, with most expected to be in place by the summer.

Shortly after his speech to the troops, Mr Obama, who is travelling on his Air Force One jet, left the country.

'Thank you'

US troops make up the majority of the Nato-led coalition⁵ force（联军） in Afghanistan.

Speaking to the large indoors gathering⁶ at Bagram, Mr Obama said: "There is no visit that I consider more important than this visit I am making now.

"My main job here today is to say thank you on behalf of the entire American people."

He added: "The Afghans have suffered for decades, decades of war, but we are here to help Afghans forge（锻造，伪造） a hard-won（来之不易的） peace... and we want to build a lasting partnership⁷ founded upon mutual⁸ interest and mutual respect."

Mr Obama said America had not chosen the war, and had not sought to meddle⁹ in（干涉，干预） Afghan affairs or expand its influence.

It had, he said, been "attacked viciously（邪恶地，故意地） on 9/11", and al-Qaeda leaders and their Taliban allies were still in the region and had to be defeated.

The US aimed to deny al-Qaeda a safe haven¹⁰ and reverse（颠倒，倒转） the Taliban's momentum¹¹, he said.

He promised troops that they were being "backed up by a clear mission and the right strategy" and that they would have "the support to get the job done".

"I'm confident all of you here are going to get the job done in Afghanistan," he said to applause and cheers.