A bomb exploded in the restroom of a cafe in Turkey's capital, killing a woman who reportedly belonged to an outlawed Marxist group and wounding another person.

Private NTV said the woman, who carried a backpack, may have planned a homicide attack and that her bomb went off prematurely.

But police and Interior Ministry officials refused to confirm the report.

"It is too soon to say anything," Deputy Chief of Police Feyzullah Aslan said. "The evidence is being examined, technical inspections are continuing."

The explosion in the restroom of the Crocodile Cafe, which occupied two floors of a 10-story building in Ankara (search)'s commercial district of Kizilay, shattered walls and windows in the building.

"I could see bits of flesh thrown all over the place," said Ali Vehbi, a student who arrived at the scene shortly after the blast, as he pointed to blood on a window opposite the cafe.

Police recovered the remains of the woman from the restroom debris.

The semiofficial Anatolia news agency, as well as other Turkish media, said the woman was a member of the Revolutionary People's Liberation Party-Front (search) or DHKP-C, a banned Marxist group, although there was no immediate claim of responsibility for the blast. Anatolia identified the woman as Songul Alpyurt from the southeastern province of Malatya.

Radical leftist, Kurdish (search) and Islamic groups are active in the country and have carried out bombings in the past.

Anatolia, citing senior police sources, said a police officer in plain clothes but carrying a walkie-talkie had been in the cafe just before the explosion. Police were investigating if the woman may have panicked and set off the bomb.

Anatolia said the woman sat at one of the tables at the cafe and ate several spoons of pudding before going to the restroom.

One of the owners, Sadullah Kayalar, said the cafe had not received any threats. The cafe, which also served fast food, was popular with students who study at dozens of nearby private schools that teach English or prepare students for university entrance exams.

It was not clear how many people were in the cafe at the time of the blast.

"It was such a terrifying explosion that we all ducked and hid under the tables," said Gokhan Ekinci who works at a travel agency immediately above the cafe. "We were all shaking."

Mustafa Gundogdu, a barber, said he heard the blast. "Smoke was coming out of the cafe," he said. "Then the windows came falling down."

The DHKP-C has claimed responsibility for a number of assassinations and bombings since the 1970s. The group is also leading a nationwide hunger strike, in which 65 people have died since October 2000, to protest Turkey's maximum security prison system.

In 2001, the group claimed responsibility for a homicide attack in which a man set off explosives near a police post at a bustling Istanbul square popular with tourists. Four people, including an Australian woman and the bomber, were killed.

The explosion Tuesday comes a month after a bomb exploded at a McDonald's restaurant in Istanbul, causing damage but no injuries. No one claimed responsibility and no suspects were caught.