Originally posted by the Voice of America. Voice of America content is produced by the Voice of America, a United States federal government-sponsored entity, and is in the public domain. Obama Rallies US Troops in Kabul, Meets With Karzai VOA News 29 March 2010 Photo: AP President Barack Obama rallies troops at Bagram Air Base in Afghanistan, Sunday, March 28, 2010. U.S. President Barack Obama has pressed Afghan President Hamid Karzai to crack down on corruption and improve his government's performance during an unannounced trip to Afghanistan. Mr. Obama's six-hour visit to Kabul began with talks at the presidential palace. He praised efforts by Mr. Karzai and his Cabinet to secure the country, but also said officials need to crack down on corruption and expand the rule of law. Mr. Karzai expressed gratitude for U.S. support and pledged his country would move forward and eventually take over its own security. The White House said President Karzai will visit Washington on May 12. President Obama also met with U.S. military officers and troops at the Bagram air base north of Kabul. He said the U.S. mission in Afghanistan is clear: to disrupt, dismantle, defeat and destroy al-Qaida and its extremist allies.  Mr. Obama stressed the importance of the troops' mission, saying it is essential to America's security. He said U.S. lives would be at risk if the Taliban regains control of the country. In southern Helman province, international forces are working to consolidate their control over territory formerly held by militant fighters. The allied team also is preparing for battle in neighboring Kandahar province, birthplace of the Taliban. Since he became president last year, Mr. Obama has shifted attention from the war in Iraq, where the United States is reducing its presence, to Afghanistan, ordering the deployment of 30,000 additional troops there. Relations between the U.S. and Mr. Karzai's government have been strained at times since the Afghan leader won re-election in a controversial ballot marred by widespread fraud. Some information for this report was provided by AP, AFP and Reuters. .