This came two days after two other opposition leaders said they had been banned from entering the emirate. 

"They told us at Kuwait airport that there is a decision to deny us entry and they sent us back to Bahrain on the same plane," Sheikh Ali Salman, head of the Islamic National Accord Association told AFP. 

"They gave no specific reasons, but we believe it is linked to the constitutional conference we held." 

Ibrahim Shareef of the leftist National Democratic Action Association (NDAA) called the ban "temporary and linked to the constitutional conference." Kuwaiti authorities were not immediately available to confirm the ban. 

But on Monday the NDAA's head Abd al-Rahman al-Nuaimi and the head of the Nationalist Democratic Rally Rasul al-Joshi said they called contacts in Kuwait who told them they were banned from entering the emirate. 

Conference

Four Bahraini opposition parties ended a conference on Sunday by telling authorities to prepare for a "serious national dialogue between the government and opposition parties in order to reach a solution to the constitutional crisis." 

Conference organisers said they would collect signatures on a
popular petition that "would express the views of the Bahraini
people" on constitutional amendments, stressing their commitment to maintaining Bahrain as a constitutional monarchy. 

But MPs issued a statement on Tuesday saying only they and the king were "responsible for constitutional changes." 

Bahraini authorities were opposed to the conference taking place and prevented three Kuwaiti MPs and activists from Britain, Jordan and France to enter the country to take part. 

Reforms

"They told us at Kuwait airport that there is a decision to deny us entry and they sent us back to Bahrain on the same plane. They gave no specific reasons, but we believe it is linked to the constitutional conference we held." 

Sheikh Ali Salman,
head of the Islamic National Accord Association

Bahrain's elected chamber was revived in 2002 as part of reforms spearheaded by King Hamad, who turned the Gulf state into a constitutional monarchy. 

It had been dissolved in 1975 after it clashed with the government over a state security law. 

The four groups are mainly opposed to the equal legislative powers accorded to the appointed Majlis al-Shura, or consultative council, which like the elected parliament has 40 members. 

All four boycotted the 2002 parliamentary polls in protest at the amendment to the 1973 constitution which split legislative power equally between the elected chamber and the consultative council.