At least 57 people were killed and more than 115 injured when near simultaneous explosions rocked three Western hotel chains in the Jordanian capital Amman last night.
Police said the blasts at around 9pm local time (7pm Irish time) were probably suicide attacks that bore the hallmark of al-Qaeda.
The hotels are frequented by American and European businessmen and diplomats.
The Radisson, in particular, is popular with Israeli tourists, and was a target of several foiled al-Qaeda plots in the past.
King Abdullah II, who was on an official visit to Kazakhstan, cut short his trip and was returning home tonight.
"There were three terrorist attacks on the Grand Hyatt, Radisson SAS and Days Inn hotels and it is believed that the blasts were suicide bombings," police spokesman Major Bashir al-Da'aja told reporters.
Another police official said the attacks were simultaneous and hit two districts in the Jordanian capital, including the commercial area of Jebel Amman and al-Rabiyeh, which houses the Israeli embassy.
"The attacks carry the trademark of al-Qaeda," said the official. "We are investigating."
Israeli embassy spokesman Jacob Raber said there were no immediate reports of Israeli casualties.
Arson experts arrived at the Grand Hyatt hotel shortly after the explosion to inspect the scene and to ensure there were no other bombs, according to a reporter on the scene.
Black smoke rose into the night and wounded stumbled out of the hotels. The stone entrance of the Grand Hyatt was completely shattered. One reporter said he saw seven bodies carried out and many more wounded on stretchers.
"It was a miracle that we made it out without a scratch," said a British guest at the Grand Hyatt.
An American guest said a bomb exploded in the lobby.
"Several of my friends have died. The people who carried this out were cowards," he said.
The blast ripped through the Radisson during a wedding party with at least 300 guests. "We thought it was fireworks for the wedding but I saw people falling to the ground," said one guest.
Amman has become a base for westerners who fly in and out of Iraq for work.
Jordanian officials blamed the attack on al-Qaeda in Iraq, and there have been growing worries that the violence in Iraq could spill over into Jordan.
The kingdom has arrested scores of Islamic militants for plotting to carry out attacks. - (AP)
The Department of Foreign Affairs last night said there were no reports of any Irish nationals being injured or among the fatalities.