A U.S. official says U.S. troops will stay in Afghanistan beyond the end of the year, in a deal to be signed on Tuesday under the country's newly inaugurated president.
The security agreement will allow about 10,000 soldiers to stay on when the international combat mission ends Dec. 31.
The development came Monday as Ashraf Ghani officially took over for outgoing President Hamid Karzai.
Under tight security, delegates from around the world joined Afghan political and religious leaders at Monday's inauguration ceremony, which was held at the presidential palace in Kabul.
Election rival Abdullah Abdullah was also sworn in as the country's new chief executive in a power-sharing deal reached after months of a post-election crisis.
U.S. Secretary of State John Kerry congratulated both leaders and praised them for turning a "moment of challenge" and turning it into a "moment of real opportunity."
In New York, United Nations Secretary-General Ban Ki-moon acknowledged serious challenges facing Afghanistan and called for the new government "to be formed quickly and to work with all Afghans in a spirit of national unity."
Inauguration day was not free from violence, however. The Taliban has claimed responsibility for the suicide attack near Kabul's airport that killed at least four people.
Ghani, who served as finance minister for two years under outgoing President Hamid Karzai, invited opposition groups - including the Taliban - to discuss the country's future.
"Fighting is not the solution to the political differences, we proved that political differences can be solved through political negotiations. Therefore I call upon the opponents of the government - especially the Taliban and Hezb-e-Islami to join political talks," he said.
The inauguration ceremony at Kabul’s presidential palace took place before a large number of foreign dignitaries, including neighboring Pakistan’s President Mamnoon Hussain and senior U.S. presidential advisor John Podesta, who announced Tuesday's security deal.
Monday’s political transition marked the end of President Hamid Karzai’s nearly 13 years in power. He was installed as leader of Afghanistan in late 2001, shortly after a U.S.-led military coalition ousted the Islamist Taliban from power for harboring the al-Qaida network.
Some information for this report was provided by AP, AFP and Reuters.