A suicide bomber in a car targeted a NATO convoy in Jalalabad in eastern Afghanistan on Friday, killing at least three Afghan civilians and wounding a dozen more, provincial officials said. (Reuters)

A suicide bomber detonated a car filled with explosives Friday near a U.S. military convoy in eastern Afghanistan, killing four Afghan civilians and wounding 10 others, the latest sign that the Taliban insurgency is ramping up its assaults after a brief winter lull.

No U.S. troops were killed or wounded, said Hazrat Hussain Mashreqiwal, a police spokesman for Nangahar province. The attack occurred about 10 a.m. as the convoy was headed back to base in the provincial capital, Jalalabad, not far from the airport, he said.

The Taliban immediately asserted responsibility for the attack.

In a second attack Friday, a roadside bomb in eastern Ghazni province killed 12 passengers in a minivan. All the victims — six women and six men — were from a single family, said Mohammad Ali, the deputy provincial governor. “It is the work of the Taliban,” he added. “They are always behind the roadside mines.”

Friday’s attack was the second assault this week against U.S. forces in Jalalabad. On Wednesday, an Afghan in military uniform, in a suspected “insider attack,” opened fire on a group of American troops protecting a U.S. Embassy diplomatic mission, killing one service member and wounding several others. U.S. troops returned fire, killing the assailant. One Afghan soldier and two others were wounded in the gun battle. No group has claimed responsibility for the attack, though suspicion is focused on the Taliban or a fringe group aligned with the insurgency.

An Afghan security officer stands at the site of a suicide attack in Kabul on April 10. (Omar Sobhani/Reuters)

That attack, which happened outside the provincial governor’s compound, occurred about eight miles from the U.S. military base near where Friday’s attack took place. The incidents highlight the threats faced by the roughly 10,000 U.S. troops who have remained in Afghanistan since the departure of most international forces at the end of last year.

The Taliban is increasing its assaults on Afghan government personnel and institutions as well as targeting those assisting the government. On Thursday, gunmen dressed in Afghan police uniforms attacked the attorney general’s office in the northern city of Mazar-e Sharif, killing 10 and wounding scores. The Taliban also claimed responsibility for that assault, which unfolded in the country’s most stable and peaceful city and took six hours to quell.

In the past three weeks, there have been several other incidents, including a suicide bombing in the southeastern city of Khost that killed 18 people and wounded scores in the middle of a demonstration against the provincial governor. Another suicide bomber killed seven and wounded 36 near the Finance Ministry and presidential palace in the capital, Kabul. And days before that, a suicide bomber assassinated an influential regional police commander.

Last year was the deadliest on record for Afghan soldiers and civilians. Most Afghan officials, including President Ashraf Ghani, say they think the nation is on the brink of a difficult spring and summer under a growing Taliban offensive. With that in mind, Ghani, during his recent visit to Washington, was able to secure an agreement from President Obama to slow the planned downsizing of U.S. forces in the country.That, both U.S. and Afghan officials hope, will allow more time to train and advise the country’s security forces, who have struggled to fill the void left by the departure of foreign troops.

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