By VIVIAN SEQUERA, Associated Press Writer

HAVANA - Activists delivered more than 11,020 signatures to Cuba's National Assembly on Friday, demanding a referendum for broad changes in Cuba's socialist system less than 48 hours before a visit here by former U.S. President Jimmy Carter.

Known as Project Varela, the signature-gathering campaign is seen as the biggest homegrown, nonviolent campaign to force reforms in the government established by Fidel Castro 43 years ago.

The petitions propose a referendum that would ask voters if they favor civil liberties like free speech, an amnesty for political prisoners, the right to start their own businesses.

Cuba's constitution says the National Assembly should schedule a national referendum if it receives the verified signatures of 10,000 legal voters.

"The heroes are these Cubans, more than 20,000 who signed this demand for an opening in a written declaration," campaign coordinator Oswaldo Paya said before entering the National Assembly, or Cuba's parliament.

Paya said that of the 20,000 signatures activists gathered in recent months, volunteers verified 11,020 — those delivered shortly before 11 a.m. to Columbia Lugo, a National Assembly secretary who deals with the public.

All of these Cubans, who with great courage and sacrifice have signed Project Varela, are the social vanguard for peaceful change in Cuba," Paya said. "In Cuba, change for all rights will only be achieved if the majority of Cubans decide to conquer them peacefully ... we are asking that the Cuban people be given a voice."

There was no immediate response from Castro's government to the move. Asked by reporters in April about the campaign, Foreign Minister Felipe Perez Roque said he doubted it would succeed and accused its organizers of being on the U.S. government payroll.

Paya, of the Christian Liberation Movement, and two men identified as Antonio Villa Sanchez and Andres Regis Iglesias, showed up outside the offices of the National Assembly with two white boxes, labeled "Citizen Petition."

Two uniformed guards let them inside, where the stayed just seven minutes.

Paya, who says the project has received no money from any government or group outside Cuba, has said state security agents have harassed the petition drive, particularly as the campaign is near its goal. He said agents had confiscated several thousand signatures, but volunteers had gone out and collected more.

Carter, who arrives Sunday at Castro's invitation, plans to meet with Cuban activists to discuss human rights and religious matters next Thursday, his staff has said. A visit with Project Varela was considered likely — especially now that they have delivered their petitions to Castro's government.

Named for Felix Varela, Cuban independence hero and Roman Catholic priest, the signature drive was discussed by activists here as early 1996. But it wasn't until the last year that volunteers begin collecting signatures in earnest.

Volunteers in recent months have verified signatures, visiting each person who signed and ensuring name, address and national identity documents match.