CASABLANCA, Morocco (AP) _ The lawyer for three Saudis accused of plotting to attack U.S. and British warships argued Friday they were wrongly detained and said there is no evidence to support the case against them.

The three were arrested May 12 in an alleged plot to sail a dinghy loaded with explosives from Morocco into the Strait of Gibraltar to attack U.S. and British warships. Prosecutors said they were also in a cell of the al-Qaida terror group.

``This dossier is empty. There is no material proof,'' said Khalil Idrissi, one of a dozen defense lawyers.

He said they were held illegally for a month, and that their arrests and interrogation ``were carried out in flagrant violation of penal procedures and international conventions on human rights.''

The trial of the three, and seven Moroccans suspected as accomplices, has moved slowly since first opening Oct. 28. It was postponed three times before reopening Friday.

The alleged plot was similar to one carried out in October 2000, when two suicide bombers in a small boat rammed the USS Cole destroyer in a port in Yemen, killing 17 sailors.

The three defendants are Zouhair Hilal Tabiti, 26, Hilal Jaber El-Assiri, 31, and Abdellah Msafer El Ghamidi, 22. They are also accused of planning to attack buses and blow up a cafe in Marrakech, a major tourist destination in this North African kingdom.

It was not known what proof the prosecution would bring to the case. Moroccan authorities have claimed the three Saudis were actively involved with al-Qaida.

The three Saudis were arrested based on information from Moroccan prisoners at the U.S. military base at Guantanamo Bay, Cuba, where more than 600 prisoners from 41 countries are being held.

Moroccan authorities were tipped off by their U.S. counterparts, and investigators made several trips to Guantanamo to interview Moroccans, officials have said.