Afghan policemen remain on guard Thursday near the site of an explosion near the U.S. Embassy in Kabul, Afghanistan. A suicide car bomber targeting an American convoy exploded about 200 yards outside the U.S. Embassy in Kabul on Thursday, killing at least four people just as American civilians were entering the compound for a Thanksgiving Day race.

Kabul, Afghanistan ? A suicide car bomber targeting a convoy of foreign troops exploded about 200 yards (meters) outside the U.S. Embassy in Kabul on Thursday, killing at least four Afghan bystanders as people entered the compound for a Thanksgiving Day race.

At least 18 others were wounded in the morning attack, said Abdullah Fahim, a health ministry spokesman. Police officer Abdul Manan said the explosion was set off by a suicide bomber in a Toyota Corolla.

No U.S. Embassy personnel were killed or injured in the blast, an embassy statement said. The Interior Ministry said the bombing targeted a convoy of foreign troops but it had no additional information.

The blast happened on the last day of a visit by a United Nations Security Council delegation. The U.N. had warned its staff in Afghanistan of possible terrorist attacks coinciding with the visit.

The U.S. Embassy was hosting a Thanksgiving Day run scheduled for 9 a.m. Americans and other Westerners were entering the embassy compound when the bomb went off — at about 8:30 a.m. — sending some participants sprinting for the embassy’s inner gates.

“There was a large explosion. I felt the shock wave, though it wasn’t all that strong,” said Danny Cutherell, a 26-year-old aid worker from Virginia.

Embassy employees are not allowed to leave the embassy’s compound in Kabul, so employees there often organize sporting events and other parties and invite Americans who live in Kabul. The Thanksgiving run has become an embassy tradition.

After a 90-minute delay, about 60 people ran the race. The winner, Casey Johnson, ran the approximately 5-kilometer course in just more than 19 minutes. Johnson, a marathon runner, ran a Thanksgiving Day fun run last year in Brooklyn. “This is quite a bit different,” he said.

David Johnson, who has been in Afghanistan for 18 months but is scheduled to leave next week, said the blast was a “capstone” on his time in the country.

“One thing I noticed is that for people here, it (the bombing) is like a nonevent,” said Johnson, 37, a San Diego native who helps run the CURE International hospital in Kabul. “People are laughing and carrying on. There are kids running around.”