An apparent suicide bomber blew himself up at an entrance to the U.S. Embassy in Ankara on Friday, killing himself and a Turkish guard and wounding at least one other person.

No Americans were injured in the attack.

White House press secretary Jay Carney told reporters in Washington that the bombing “was clearly an act of terror.”

The blast occurred about 1:15 p.m. at the entrance to the visa section of the embassy. It sent chunks of concrete and other debris flying into the street outside the well-fortified compound.

According to one report, the bomber was going through security inside the building when he detonated the charge strapped to his body. Police quickly cordoned off the area, keeping the crowds well back from the scene.

There was no immediate claim of responsibility for the attack. But Turkish Interior Minister Muammer Güler described the bomber as a member of an outlawed leftist organization, apparently a reference to the Revolutionary People’s Liberation Party-Front.

The Marxist-Leninist group, known by the acronym DHKP-C, has been active in Turkey since the 1970s, occasionally carrying out attacks against American and other foreign targets.

American officials were initially worried that the bombing may have been the work of al Qaeda. Islamic militants linked to the group have carried out several attacks in Turkey over the years, including truck bombings in late 2003 that killed nearly 70 people.

But Turkish officials seemed convinced that Islamic militants were not involved this time.

Soner Cagaptay, an expert on Turkey at the Washington Institute for Near East Policy, says the DHKP-C had its heyday in the 1970s and ’80s, but lost much of its influence after a series of crackdowns by Turkish authorities.

“It went from being a group with mass appeal to one with just a few hundred members. Its telltale sign has been attacks on U.S. missions. So this is not surprising,” Cagaptay tells The Daily Beast.

“They see the world through the prism of the Cold War. It’s really kind of surprising they’re still around,” he adds.

Cagaptay says leftist groups have lately been protesting the NATO deployment of Patriot antimissile batteries on Turkish soil. The batteries are intended to protect Turkey from rocket attacks by neighboring Syria, where a civil war has raged for nearly two years and killed more than 60,000 people.

Turkey is largely sympathetic to the rebels in Syria and has called on President Bashar al-Assad to step down.

Nuh Yilmaz, a Turkish political analyst and visiting fellow at European Council on Foreign Relations, says some recent press reports have suggested that the DHKP-C is getting support from Assad’s regime.

“There is a revival of the group. There might be a connection between the Syria crisis and the new strength of this group,” Yilmaz says.

“This most likely can be seen as an extension of what’s going on in Syria—as the spillover into Turkey.”

Turkish media reported last week that scores of people connected to DHKP-C were arrested around the country on suspicion of providing state secrets to neighboring Greece and Syria. Among those detained were 11 lawyers, according to the reports.

It wasn’t immediately clear if there was any connection between the arrests and Friday’s bombing.