Jerusalem: Cypriot authorities have detained an Iranian ship en route to Syria with a cargo of weapons, Israel's Haaretz newspaper reported on Friday.

Quoting a European Union diplomatic source, it said Cyprus had acted after Israel and the United States requested that the Cypriot-flagged vessel be stopped.

Authorities contacted the ship and demanded that it dock in Limassol for inspection. Customs officials had unloaded part of the cargo and a large amount of weaponry, including artillery rounds and rockets, the paper said.

Cypriot authorities declined comment.

Israel believes the weapons were destined for the Lebanese Islamist guerrilla group Hezbollah or for Islamist Hamas militants in the Gaza Strip, Haaretz quoted Israeli sources as saying.

On Wednesday, US military officials said personnel from the US Navy vessel San Antonio last week boarded the Cypriot-flagged "Monchegorsk", a cargo vessel travelling from Iran to Syria, and found a weapons shipment but for legal reasons did not confiscate the cargo.

The officials declined to say what kind of weapons were found or how many. They also would not say where or when the incident occurred.

It was unclear whether this was the same ship which Haaretz reported had been apprehended by the Cypriot authorities.

Officials in Washington said the search was conducted as part of the US Navy's normal maritime security role in regional waters that stretch from the Arabian Sea to the Mediterranean.

The US officials said the arms could not be shown to have violated UN weapons sanctions against Iran and the vessel was allowed to continue to Syria.

The incident came to light amid media reports that the US navy has been ordered to intercept suspected Iranian shipments to rearm Hamas following Israel's 22-day offensive in Gaza.