Dubai police investigating the killing of a senior Hamas commander in a hotel room in the Gulf emirate last month said today an 11-member hit squad, three of whom had Irish passports, was responsible for the murder.

Dubai's police chief did not directly implicate Israel in the assassination as the Islamic militant group has. Photos, names, nationalities and passport numbers of all 11 suspects have been released by police.

The details given by Lt. Gen. Dhahi Khalfan Tamim are the most comprehensive accusations by Dubai authorities since the body of Mahmoud al-Mabhouh was found Jan. 20 in his luxury hotel room near Dubai's international airport.

Tamim said it was possible that "leaders of certain countries gave orders to their intelligence agents to kill" al-Mabhouh, one of the founders of Hamas' military wing. But he did not name any countries.

Hamas has blamed Israel and vowed revenge.

Tamim sketched out a highly organised operation in the hours before the killing, clearly done with advance knowledge of the victim's movements, and said the killers spent less than a day in the country. He said forensic tests indicate al-Mabhouh died of suffocation, but lab analyses are still under way to pinpoint possible other factors in his death.

He showed a news conference surveillance video of the alleged assassination team arriving on separate flights to Dubai the day before al-Mabhouh was found dead. The members of the alleged hit-squad checked into separate hotels.

They paid for all expenses in cash and used different mobile phone cards to avoid traces, he added.

At least two suspected members of the team watched al-Mabhouh check in to his hotel and later booked a room across from the Hamas commander, Tamim said.

He added that there was "serious penetration into al-Mabhouh's security prior to his arrival" in Dubai, but that it appeared al-Mabhouh was traveling alone.

"Hamas did not tell us who he was. He was walking around alone," said Tamim. "If he was such an important leader, why didn't he have people escorting him?"

Tamim said there was at least one unsuccessful attempt to break into al-Mabhouh's hotel room. It was unclear whether he opened the door to his killers or if the room was forcibly entered.

The killing took place about five hours after al-Mabhouh arrived at the hotel and all the 11 suspects were out of the United Arab Emirates within 19 hours of their arrivals, he added.

Tamim claimed the suspects left behind some evidence, but he declined to elaborate. He urged the countries linked to the alleged killers to co-operate with the investigation.

Tamim told reporters the alleged assassination team comprised six British passport holders, three Irish and one each from France and Germany. Hamas has accused Israel's Mossad secret service of carrying out the killing and has pledged to strike back.

Israeli officials have accused al-Mabhouh of helping smuggle rockets into Gaza.

Senior Hamas figures have denied reports that al-Mabhouh was en route to Iran, which is a major Hamas backer. But the group has not given clear reasons for his presence in Dubai.

A Hamas statement last month acknowledged al-Mabhouh was involved in the kidnapping and killing of two Israeli soldiers in 1989 and said he was still playing a "continuous role in supporting his brothers in the resistance inside the occupied homeland" at the time of his death.

More than 2,000 mourners attended al-Mabhouh's funeral and burial at the Palestinian refugee camp of Yarmouk, near Damascus, Syria.