Three missiles have been fired from the Jordanian port of Aqaba, missing a US Navy ship but hitting Israel.
All three missiles were fired from Jordanian territory
Two rockets missed the USS Ashland, an American naval ship docked in the port. A Jordanian soldier died when one of the two missiles hit the dockside.
The third missile landed near Eilat airport in neighbouring Israel, causing no injuries.
An internet statement, purportedly from a group which says it has links to al-Qaeda, said it was to blame.
The statement, allegedly from the Abdullah al-Azzam Brigades, said the attacks were the group's first attack in Jordan and were aimed at both the US and Israel.
"The Zionists are a legitimate target and we warn the Americans, who are spreading their corruption throughout the world and who have stolen the wealth of the Muslim nation, to expect even more attacks," it said.
The group is one of several to have said it carried out the bombings on a market and hotels in the Egyptian resort of Sharm al-Sheikh on 23 July.
Jordanian police are searching for two Iraqis and a Syrian thought to have rented an industrial warehouse from which the rockets were fired.
"I can confirm that a rocket flew over the bow of USS Ashland and the rocket impacted in the roof of a warehouse. No sailors or marines were injured," said Commander Jeff Breslau, of the US Fifth Fleet.
The Jordanian soldier who died was on the dockside when he was hit. He was taken to hospital where he died of his wounds, a security source said.
Another Jordanian was injured in the attack.
Katyusha rockets were used in all three attacks, officials say.
The USS Ashland and its sister amphibious ship, the USS Kearsarge, have been docked in Aqaba, Jordan's only sea port, for the past 10 days, witnesses said.
Both ships are reported to have left the port in response to the attack.
Correspondents say the attack is the most serious on a US navy ship since the bombing of the USS Cole in Yemen in 2000 that killed 17 sailors.
The third rocket hit a taxi on the outskirts of Eilat airport, but did not explode, Israeli police reported.
The missile created a small crater in the road, about 15m from the airport fence, local police commander, Avi Azulin told the Associated Press.
The commander said the rocket was fired from nearby Jordan.
Aqaba and Eilat are about 15km (9 miles) apart, located at the northern end of the Red Sea.
Israeli Defence Minister Shaul Mofaz said the attacks were "intended to hit the Israeli side and the Jordanian side as well".
"We still don't know who is behind this act," he said.