Istanbul, Turkey (CNN) -- Turkish authorities reinforced police presence Monday around Istanbul's central Taksim Square, a day after a bomber detonated explosives there, killing himself and wounding 32 people.
"It's tense," said an owner of a nearby café who asked not to be identified. His business is but one of the hundreds of bars and restaurants around Taksim, in what is the most congested entertainment district in Turkey's largest city.
On Monday, the Anti-Terror Unit of the Istanbul police department distributed a photo of a balding, dark-haired man that police officers said he was the man who carried out the attack. However, Turkish authorities have so far avoided naming the dead bomber or any organized group they suspect may have been behind the attack. They have also played down the fact that Sunday's strike appeared to be a suicide bombing.
Meanwhile, in a phone interview with CNN, a spokesman for the Kurdistan Workers Party, or PKK, denied responsibility for the attack.
"Some circles are pointing to our movement as the ones who are responsible for this. This is not the reality," said PKK spokesman Roj Welat, speaking by telephone from Northern Iraq where the rebel group's leadership is based. "We do not have any connection whatsoever with this action."
At a news conference Monday, Interior Minister Besir Atalay ruled out any possibility that there was a second attacker. He said that the police posted in Taksim Square were the clear target of the bombing, and that the bomber had not previously been under police surveillance.
"We have information, however we are being cautious... we do not want wrong information or mis-information to be released," Ataly said in a televised news conference. "We are not able to make a statement yet about the suspect or which organization was behind the attack."
So far, there has been no claim of responsibility for the bombing.
In recent decades, bombings and other acts of political violence have been carried out in Turkey by a broad spectrum of home-grown groups, ranging from leftists, to al Qaeda operatives, ultra-nationalists, and Kurdish separatists.
In the immediate aftermath of the explosion, some Turkish commentators cast blame on the PKK, the rebel group which has fought longest and hardest against the Turkish state.
The timing of the bombing was also suspect. The PKK had previously announced that one of its periodic "unilateral cease-fires" was due to expire on Sunday, October 31.
But in his phone interview with CNN, Welat, the PKK spokesman, announced that the rebels had decided to extend their cease-fire until after Turkey holds general elections, which are expected to take place sometime next summer.
For months there have been rumors in the Turkish media of some kind of talks taking place between PKK leader Abdullah Ocalan and the Turkish government. Ocalan has spent the last decade imprisoned on an island in Turkey's Marmara Sea.
U.S. Secretary of State Hillary Clinton released a statement Sunday condemning what she called a "terrorist attack ... which brutally targeted innocent civilians in one of the city's busiest squares."
Municipal employees worked hard to clean up evidence of the attack Sunday. Within hours, the pavement in Taksim square had been scrubbed clean of blood and body-parts. By nightfall Sunday, tourists were posing for photos in front of the square's central monument. Just a few yards from where the blast erupted, street vendors were once again selling flowers and roasted chestnuts as if nothing had happened.