Washington -LRB- CNN -RRB- -- President Obama returned to the United States on Monday morning after an unannounced visit to Afghanistan , where he met with his Afghan counterpart and reiterated the need to wipe out terror networks . Obama slipped into Bagram Air Base near Kabul under the cover of darkness Sunday . He met with about 2,000 troops at the U.S. base and told them their work is significant to security at home . `` I know it 's not easy , '' he said . `` If I thought for a minute that America 's vital interests were not served , were not at stake here in Afghanistan , I would order all of you home right away . '' The United States has made progress in the fight against al Qaeda and its allies , Obama said . `` All of that makes America safer , and we are going to keep them on the run , '' he said . `` Because that is what is going to be required in order to ensure that our families back home have the security that they need . '' Earlier , Obama met with President Hamid Karzai to discuss progress by the Afghan government in strengthening its ability to run the country and provide security for its people . After the 30-minute meeting , Obama said he wanted to send a `` strong message '' that the partnership between the nations would continue . Related : Afghanistan Crossroads Karzai thanked the United States , pointing out that American taxpayers have helped rebuild his country . During his trip , the president made clear that the visit was to encourage the roughly 80,000 U.S. troops in the country . `` The United States of America does not quit once it starts on something . ... We keep at it , '' he told the troops . `` We persevere . And together , with our partners , we will prevail . I am absolutely confident of that . '' Before his departure , Obama also met with U.S. Ambassador Karl Eikenberry and Gen. Stanley McChrystal , the commander of allied troops in Afghanistan . The trip began in secrecy , with the president leaving his Camp David retreat . He flew to Afghanistan on Air Force One , landing at Bagram Air Base at 7:24 p.m. Sunday . Obama then flew on a helicopter to the Presidential Palace to meet with Karzai . The U.S. president landed at Andrews Air Force Base in Maryland shortly before 9 a.m. ET .