KABUL, Afghanistan (AP) — Taliban suicide bombers struck two buses carrying Afghan soldiers in Kabul early Wednesday, killing seven people and wounding 21, just a day after the signing of a key U.S.-Afghan security pact.

The long-awaited deal allows U.S. forces to remain in the country past the end of 2014, ending the uncertainty over the fate of foreign troops supporting Afghans as they take over the fight against the Taliban insurgency.

Wednesday’s attacks involved two suicide bombers targeting buses carrying Afghan troops in the country’s capital.

The first attacker hit a bus with Afghan National Army officers in west Kabul, killing seven and wounding 15, said the city’s criminal investigation police chief Mohammad Farid Afzali.

The second attacker, who was also on foot, blew himself up in front of a bus in northeastern Kabul, wounding at least six army personnel, Afzali said.

Taliban spokesman Zabihullah Mujahid claimed responsibility for the attacks, saying the security pact with America has only motivated the group and given the Taliban “more morale” to fight the enemy.

“They need to give more sacrifices to make their homeland free,” Mujahid said, referring to Taliban fighters.

In a separate statement to media, the Taliban denounced the Bilateral Security Agreement as an “American plot” and said that “such fake documents will never hold back the lawful jihad,” or holy war.

In Kabul, dozens of Afghan security forces sealed off the attack sites, littered with broken glass, as military ambulances took the victims to hospital. Worried Afghans passed by, on their way to work.

Under the security pact, along with a separate deal signed with NATO, about 10,000 American troops and several thousand more from other NATO countries will stay to train and advise Afghan forces after the international combat mission ends on Dec. 31.

More than a decade after U.S. forces helped topple the Taliban in the wake of the Sept. 11 attacks, Afghanistan is still at war with the Islamic militant group, which regularly carries out attacks, mainly targeting security forces.

There are also serious questions about the ability of the Afghan security forces to take on the militants, even with a residual U.S. force remaining in the country.

In other violence, two police officers were killed when a suicide bomber targeted a police vehicle late Tuesday in Lashkar Gah, the capital of southern Helmand province. Five policemen were also wounded in the attack, Omar Zwak, the spokesman for the provincial governor said Wednesday.

The U.S.-Afghan pact was long in the making. U.S. officials had first warned their Afghan counterparts that if the security accord was not signed by the end of 2013, the Pentagon would have to start planning for a full withdrawal of troops from Afghanistan.

But when the year ended, the White House moved back the deadline, saying then-President Hamid Karzai needed to sign off within weeks. Karzai surprised U.S. officials by ultimately saying he would not sign the accord and would instead leave that task for his successor.

But the results of the race to replace Karzai took months resolve, finally coming to a conclusion on Monday with the swearing in of Ashraf Ghani Ahmadzai as Afghanistan’s second elected president.

Ghani Ahmadzai signed the security agreement Tuesday, nearly one year after the White House’s initial deadline.

Later Wednesday at a ceremony in Kabul, Ghani Ahmadzai officially introduced his former rival for the presidency, Abdullah Abdullah, as the country’s new chief executive, a post akin to prime minister.

Abdullah pledged to “serve the people and the nation” and urged Afghans to have faith in the new administration.

Abdullah’s post was created after he and Ghani Ahmadzai struck a U.S.-brokered power-sharing agreement last month after a prolonged dispute over alleged voting fraud in June’s presidential runoff.

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Associated Press writer Mirwais Khan contributed to this report from Kandahar, Afghanistan.