"Security forces today received three Saudi citizens convicted and jailed in Morocco on security-related charges," said an interior ministry official quoted by the state SPA news agency.
He named them as Abd Allah bin Misfir al-Ghamdi, Zuhair bin Hilal al-Thibiti and Hilal bin Jabir al-Assiri, who were sentenced by a Casablanca court in February 2003 to 10 years in prison, for plotting attacks against Western targets in Morocco and the Strait of Gibraltar.
"The kingdom handed over to Moroccan security authorities two Moroccan nationals (wanted) for security-related issues," the official said.
He identified the pair as Ali bin Idris al-Uzli and Muhammad bin Muhammad Alwan.
On 6 December, Saudi Arabia named two other Moroccans - Husayn Muhammad al-Haski and Karim al-Tuhami al-Majati - among 26 suspects wanted for involvement in "terror acts" in the kingdom.
The list also included a Yemeni, while the rest were Saudis, one of whom has since been killed in clashes with security forces while another surrendered, according to Riyadh.
The interior ministry official did not give details about the Moroccans handed over to Rabat, but a Saudi security source told AFP on condition of anonymity the pair had been "arrested on charges of starting to plot terror acts with other" suspects.
Sunday's swap "comes within the framework of cooperation between security authorities in the two brotherly countries," said the official cited by SPA.
The three Saudis were accused of being part of a cell of Saudi-born Usama bin Ladin's al-Qaida network.
Bombings in Saudi resulted in deaths
of several people, mostly foreigners
The court in Casablanca said the three were guilty of "having formed a criminal gang" but did not mention al-Qaida.
Three Moroccan women, two of them married to two of the Saudi defendants, were sentenced to six months in jail. Three other Moroccans received sentences ranging from four months to one year.
One Moroccan was acquitted.
Prosecutors had asked for the death penalty for the Saudi defendants and the two Moroccan spouses.
The five were charged with planning to use Zodiacs - motorized rubber dinghies - to blow up US and NATO ships in the Strait of Gibraltar and to attack tourist spots in Morocco, including Marrakesh's Jemaa al-Fna Square.
The Saudi security source said the three Saudis would serve the rest of their sentences in prison in Saudi Arabia.
Hundreds of suspected insurgents were rounded up in the wake of three simultaneous attacks on expatriate housing complexes in the Saudi capital on 12 May which killed 35 people, including eight Americans
Saudi Arabia's ambassador in Morocco, Abd al-Aziz Khoja, had told AFP on Saturday the three would imminently be handed over to the kingdom and the two Moroccan spouses would join them at a later date after serving their sentences.
"Relatives of (the three men) will be able to visit them," the interior ministry official said, according to SPA.
Hit by a string of deadly bombings last year, Saudi Arabia has launched a massive crackdown on insurgents, believed linked to al-Qaida.
Hundreds of suspected insurgents were rounded up in the wake of three simultaneous attacks on expatriate housing complexes in the Saudi capital on 12 May which killed 35 people, including eight Americans.
A series of similar bombings in Casablanca four days later left more than 40 people dead.
In Riyadh, suspected al-Qaida bombers struck again on 8 November, setting off a car bomb in another expatriate housing complex and killing 17 people, mostly Arabs.