A suicide bomber struck a NATO convoy Sunday morning, killing four people, as the Taliban continues a final assault on the foreign troops who are leaving the “Graveyard of Empires.”

NATO and Afghan security forces inspect at the site of a suicide attack in Kabul, Afghanistan, Sunday, Aug. 10, 2014. A suicide car bomber attacked a NATO convoy moving through Afghanistan’s capital Sunday, killing several civilians and wounding more than 35 in an assault claimed by the Taliban, authorities said. (AP Photo/Rahmat Gul)

As the Associated Press reported:

A suicide car bomber attacked a NATO convoy moving through Afghanistan’s capital Sunday, killing at least four civilians and wounding more than 35 in an assault claimed by the Taliban, authorities said.

The blast struck two MRAPs, or Mine Resistant Ambush Protected armored vehicles, in western Kabul, damaging a civilian car and leaving debris scattered across a highway lined by shops. NATO troops and Afghan soldiers cordoned off the scene after the blast.

Hashmat Stanikzai, a spokesman for Kabul’s police chief, said the blast killed four civilians and wounded more than 35 people. NATO later said the blast wounded none of its troops, though it was investigating the attack.

NATO forces patrol the site of a suicide attack in Kabul, Afghanistan, Sunday, Aug. 10, 2014. A suicide car bomber attacked a NATO convoy moving through Afghanistan’s capital Sunday, killing several civilians and wounding more than 35 in an assault claimed by the Taliban, authorities said. (AP Photo/Rahmat Gul)

“The explosion was so strong and many people were killed and wounded,” witness Mohammad Amin told the AP.

Afghan shopkeepers clean up broken glasses near the site of a suicide attack in Kabul, Afghanistan, Sunday, Aug. 10, 2014. A suicide car bomber attacked a NATO convoy moving through Afghanistan’s capital Sunday, killing several civilians and wounding more than 35 in an assault claimed by the Taliban, authorities said. (AP Photo/Rahmat Gul)

As the AP noted, the Taliban has been vocal about increasing attacks, seeking to undermine the Afghan government as foreign combat troops leave Afghanistan this year.

In July, a remote town was rocked by Afghanistan’s deadliest blast since 2001 when a suicide bomber detonated in a marketplace, killing 89 people.

Last week, American Maj. Gen. Harold Greene was killed and 15 other people were wounded in a “green on blue” attack, when a man in an Afghan military uniform opened fire at the Afghan military academy in Kabul.

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