KABUL, Afghanistan — Two NATO service members, including an American, were killed in Kabul on Thursday, military officials said, just days after the top U.S. negotiator in peace talks with the Taliban said he had reached a peace deal “in principle.”

The U.S. and Romanian troops died in a Taliban-claimed car bombing in a heavily fortified part of central Kabul just after 10 a.m., a NATO official confirmed. The Interior Ministry originally said 10 people had died in the attack.

This brings the number of U.S. troops killed in combat in Afghanistan to 16 this year. A U.S. Green Beret from Idaho was killed in southeastern Zabul province Aug. 29. The identity of the U.S. service member killed Thursday is being withheld until the family has been notified.

Over the past week, as U.S. envoy Zalmay Khalilzad has met with top Afghan officials to brief them on the peace agreement, the Taliban has ramped up its attacks, killing dozens of civilians, Afghan security forces and foreigners. In the past three days, more than 20 people have been killed in Taliban bombings in Kabul, including a Romanian diplomat. The group also has launched offensives in the northern cities of Kunduz and Pol-e Khomri.

“Our attacks currently are in reaction to the long wave of offensives by foreign troops, which also involves local forces against civilians,” Taliban spokesman Zabiullah Mujahid said in a phone call Thursday.

The Afghan government has been excluded from nine rounds of U.S. peace talks with the Taliban in Qatar, and this week’s attacks have reinforced concerns among Afghan leaders that the proposed agreement does not offer strong enough guarantees that Afghan security forces and civilians will be protected as U.S. troops draw down.

In an interview with the conservative news website Daily Signal this week, Secretary of State Mike Pompeo said the United States “has delivered” on its original goal in Afghanistan — to defeat al-Qaida, the terrorist organization responsible for the 9/11 attacks.

Under the draft agreement, 5,400 U.S. troops would leave Afghanistan, and five U.S. bases would close within about five months, pending President Donald Trump’s approval.

At a campaign rally in Kabul after the explosion Thursday, President Ashraf Ghani’s running mate, Amrullah Saleh, said of the peace talks: “This is a conspiracy. It is not peace.”

“This is aimed at the division of Afghanistan, and we do not accept it,” he added.

Harun Mir, an Afghan political analyst, said Afghans are especially concerned that the deal may not include a comprehensive cease-fire. If attacks against Afghan security forces continue, he said, it will undermine the U.S. mission in Afghanistan, which is supporting the Afghan military.

Talks between the Taliban and Afghan officials are expected to immediately follow any peace deal between Washington and the Taliban. But disputes have emerged over the makeup of the Afghan government delegation and which topics will be on the table.

“There has to be at least an internal consensus among the Afghan political elite about what must be discussed with the Taliban, and so far we don’t have this consensus in Kabul,” Mir said. “We cannot engage in serious talks with this high degree of uncertainty.”

On Thursday morning, plumes of smoke could be seen rising over the capital as casualties were transported to nearby hospitals.

In footage circulating on social media, a van is seen entering a crowded traffic circle before exploding close to two white SUVs, several sedans and some pedestrians, including one who appeared to try to run from the scene just before the bomb detonated. In Kabul, white SUVs are often armored and used by diplomats, military officers and government officials.

The bombing came less than three days after a massive bomb detonated in eastern Kabul, just outside a compound housing foreigners, as Khalilzad appeared on Afghan television station ToloNews to discuss the agreement.

The Taliban claimed responsibility for that attack, which killed at least 16 people, mainly Afghan civilians. The blast also ignited anger in the neighborhood housing the compound, known as the Green Village, where Afghan residents have been killed in earlier attacks targeting foreigners.

Also Thursday, local media outlets reported that Abdul Samad Amiri, a prominent human rights defender in central Afghanistan, was kidnapped and killed in a Taliban-controlled area. Amnesty International condemned his killing, saying that “even as the Taliban claims to be pursuing peace, it continues to kill people in the most gruesome way.”