ISTANBUL, Turkey - A previously unknown Kurdish group has claimed responsibility for pre-dawn bomb attacks last Tuesday against two hotels in Istanbul's tourist districts that killed two people and injured 11 others.

An al-Qaida-linked group also claimed responsibility for the bomb attacks in a statement posted on a website but Turkish authorities cast doubt on the claim saying Kurdish separatists are suspected.

Bombs rocked the two Istanbul hotels, which provide inexpensive accommodation and are popular with foreign tourists, before dawn. Two other explosions at a liquefied petroleum gas plant on the outskirts of the city caused damage but no injuries, authorities said.

An Iranian and a Turk were killed in the hotel explosions. The injured included four Spanish tourists, two Dutch tourists, a Ukrainian and one Chinese tourist named Chen Pingzhou.

Chen suffered a slight injury to his forehead and his left arm was cut by flying glass.

The Germany-based Mezopotamya News Agency, which often reports rebel statements, said it had received a telephone call from an individual claiming responsibility for the attacks in the name of the Kurdistan Freedom Falcons Organization - a previously unknown Kurdish group.

It said the group carried out the attacks because of recent Turkish military operations against the rebels.

The Abu Hafs al-Masri Brigades, named for an al-Qaida commander killed in Afghanistan, also claimed responsibility saying the attacks were the first of a "wave of operations" in European countries and that worse was to come. It was not possible to check the authenticity of the claims.

Western experts have questioned the credibility of the Abu Hafs al-Masri Brigades, noting it has previously claimed to be behind events in which it clearly didn't play a role, such as power failures in North America and Britain.

A senior Turkish police official, speaking on condition of anonymity, said Turkish authorities had no information to suggest any links to al-Qaida, and police suspected Kurdish rebels.

Worsening security

Another police official said that the explosives used in Tuesday's attacks were similar to those used in a July car bombing in Turkey's eastern Van province that killed three people and injured two dozen others. The attack was blamed on Kurdish militants who, however, denied involvement.

Interior Minister Abdulkadir Aksu said police were still investigating the possibility that other groups could have been involved.

Security concerns in Turkey have been heightened since November, when four suicide truck bombings blamed on al-Qaida killed more than 60 people in Istanbul. The Abu Hafs al-Masri Brigades also claimed responsibility for those attacks.

Aksu said police were investigating whether the attack at the liquefied petroleum gas plant on the outskirts of Istanbul was linked to the hotel blasts.

The explosions came only hours after the arrest of four Kurdish militants. Private NTV television said the militants were preparing large-scale attacks in Istanbul.

Kurdish rebels battling Turkish troops in the southeast for autonomy have intensified attacks lately. The rebel group, known as Kongra-Gel but formerly called the PKK, had threatened to target the country's tourism industry and infrastructure when it broke a unilateral cease-fire on June 1, saying Turkey had not responded in kind.

"Explosive devices and guns were seized along with these four people. Every link is being investigated. It could be the same group," Aksu said.

Analysts have said that the rebels appear recently to have split into several factions. It was not immediately clear if the Kurdistan Freedom Falcons Organization was one such group.

Workers at the Pars Hotel in the Laleli district, where inexpensive hotels and clothing stores cater to Eastern European tourists, said they received an anonymous call saying there was a bomb in a room only 10 minutes before the explosion.

The two dead were killed in the blast at the Pars hotel. Nine of the injured were released from hospital after treatment. The hotel is also frequented by Middle Eastern visitors.

At the Star Holiday Hotel, in the heart of Istanbul's Sultanahmet tourist district and only a few hundred metres from landmarks like the Saint Sophia and Blue Mosque, glass and chunks of concrete littered the streets.

The explosion ripped off the exterior walls of the top two floors of the three-storey hotel, where 20 guests were staying.

The latest blasts occurred a few kilometres from the hotel where the US Olympic men's basketball team is staying on its final stop before the Athens Olympics.

Team officials met Tuesday morning to discuss the bombing, and a decision was made to proceed with an upcoming game, US team spokesman Brian McIntyre said.

(Agencies via Xinhua)