Kabul:US Defense Secretary Ashton Carter arrived in Kabul on Tuesday in an unannounced visit to hold talks with Afghan leaders and US military officials in the country, a source said. "Carter arrived here around midday. He will meet Afghan President Ashraf Ghani, Chief Executive Abdullah Abdullah and Afghan Defence Minister Abdullah Khan Habibi later on the day," a source told Xinhua news agency. The Pentagon chief will also meet US and NATO military commanders in the country during his trip, he said. Foreign dignitaries usually pay unannounced visit to militancy-hit Afghanistan and return to their home countries secretly due to security concerns. The NATO and US forces completed their combat mission in Afghanistan by the end of 2014, after 13 years of military presence in the country. Nearly 13,000 foreign forces, including some 9,800 US troops, are currently stationed in Afghanistan for the NATO-led Resolute Support mission to help Afghan forces in the field of training, advising and backing the troops in the war on insurgents.