"Afghanistan remains a very dangerous place," Obama said at a news conference with Afghan President Ashraf Ghani at the White House. "Insurgents still launch attacks, including cowardly suicide bombings against civilians."

　　The United States is determined to maintain the gains made by U.S. forces in the country, Obama emphasized. He said U.S. forces would continue to advise and train Afghan troops, as well as assist them in targeted counterterrorism operations.

　　Obama Won Draw Down US Troops in Afghanistan in 2015

　　Also, U.S. military leaders have seemed receptive to Ghani's request that U.S. bases in Jalalabad and in Kandahar, where the Taliban had their capital until 2001, stay open as long as possible.

　　Obama previously had announced plans to cut the troop level to 5,500 by year's end and even fewer troops by the time he leaves office in early 2017. The president said that the timeline would be reworked later this year and that the date for a final troop drawdown remained the same.

　　Ghani said flexibility provided by slowing down the U.S. troop withdrawal "will be used to accelerate reforms, to ensure that the Afghan National Security Forces are much better led, equipped, trained and are focused on their fundamental mission."

　　Obama pointedly noted that despite the drawdown of U.S. troops — the level peaked at just over 100,000 several years ago — the Afghan national army has assumed responsibility for the country's security and has not collapsed, as was predicted.

　　The U.S. administration will ask Congress for funding to allow the Afghan National Security Forces to maintain a level of 352,000 troops through at least fiscal 2017, it was announced Monday after Ghani and Abdullah Abdullah, his chief executive in a power-sharing government, met with other high-ranking officials at Camp David.

　　The Afghan leaders' U.S. trip is aimed at improving bilateral relations strained by years of war and often testy White House relations with former Afghan President Hamid Karzai.

　　Obama noted that the U.S.-educated Ghani, like the American president's own mother, trained as an anthropologist, a profession he said was committed to cultural understanding and peace. Obama said he believed "the progress we've made in this visit" has advanced "the goal of making our world safer."

　　Honoring war dead

　　Before meeting Obama, Ghani and Abdullah headed to Arlington National Cemetery, where many of the 2,300 U.S. troops killed in Afghanistan are buried. They placed a wreath at the Tomb of the Unknowns, which honors unidentified war dead.

　　At the White House briefing, Ghani again thanked U.S. troops, as well as Afghan soldiers and civilians, for their roles in helping the young democracy.

　　He also expressed gratitude to veterans' families and "the American taxpayer for his and her hard-earned dollars" in supporting Afghanistan.

　　When asked why U.S. troops should continue to sacrifice in Afghanistan, Ghani said the need for security cooperation is paramount in an interconnected world. He also said Afghanistan had embraced democratic ways while staying true to its Islamic roots.

　　While not naming the Islamic State militant group, the Afghan president referenced a “changing ecology of terror” that has made cooperation among regional governments imperative.

　　“Today, the state system as we have known it is under attack. These are not classic, national liberation movements. These are destructive, nihilistic movements, and it’s essential that we confront them with vigor and determination,” Ghani said.

　　He said Afghanistan would not have peace with those who use Afghan territory as a proxy for other purposes, as a battleground for “alien forces” or a launching pad for global terrorism.

　　The Afghan leader vowed to defeat Taliban insurgents seeking to overthrow his fledgling government in fighting that continues more than 13 years after the United States invaded Afghanistan to attack al-Qaida militants after their 2001 terrorist assault on the U.S.

　　In a stark reminder of the violence still racking Afghanistan, gunmen killed 13 bus passengers in a province near Kabul early Tuesday.