Jordan's King Abdullah

Jordan's King Abdullah has vowed to track down and bring to justice the militants who helped plan suicide bombings that killed 56 people and wounded more than 100 others in Amman.

In a speech on national television, the king said the country knows no fear and would continue fighting terrorism.

Earlier Thursday, hundreds of Jordanians marched to condemn the Wednesday attacks at three hotels. Some protesters chanted, "death to Abu Musab al-Zarqawi," the Jordanian-born leader of al-Qaida in Iraq, which claimed responsibility for the blasts.

The claim could not be immediately verified, but Jordanian Deputy Prime Minister Marwan Muasher said Abu Musab al-Zarqawi is a prime suspect. He added that several people had been detained and are being questioned.

Government officials said most of the dead are Jordanians, but at least 12 foreigners have been identified, including one American.