A suicide car bomber slammed into a convoy of foreign forces in the Afghan capital on Tuesday, the Ministry of Interior spokesman said, but it was not clear whether there were any casualties.
The attack was the second in a week targeting remaining foreign forces in the heavily fortified capital, Kabul. Most NATO troops withdrew at the end of last year.
"I can confirm that a suicide car bomber targeted foreign forces but we don't have details on casualties," ministry spokesman Sediq Sediqqi told Reuters, adding that the attack took place in the Shah Shaheed area of eastern Kabul.
Last week, a Taliban car bomber targeted a convoy of NATO troops in Kabul, killing one civilian and wounding up to 12.
Two coalition soldiers also suffered light wounds in last week's attack.
Security has deteriorated across the country as Taliban insurgents have stepped up their attacks after most foreign combat troops left Afghanistan at the end of 2014.
There are around 9,800 U.S troops remaining in Afghanistan, down from a peak around 100,000 in 2011. The majority are training Afghan forces but a contingent of a few thousand are still engaged in combat.
U.S. Senator John McCain of Arizona, visiting Kabul on Saturday, told reporters that Taliban attacks had increased and U.S. troops should stay longer than planned to prevent the militants from making gains.