HAVANA-(AP) -- Fidel Castro's government is responding to calls for reforms in this country's one-party system with its own proposal: a constitutional amendment ratifying Cuba as a socialist state.

Castro has called for a massive march for this morning in Havana and in cities across the island to support the amendment, announced exactly one month after a group of activists submitted a proposed referendum for deep reforms in the socialist system. Castro said Monday that such a march "has never been done before." In Havana, at least one million people are expected to participate.

"It will put our organizational ability to the test . . . to organize the march in all of the country's provincial capitals, in all of the country's municipalities," Castro said after a gathering of the national leadership of the government's popular support organizations. "Where there are houses, there will be a march," he added.

The proposed constitutional amendment declaring Cuba's socialist system to be "untouchable," and the massive mobilization, appear to be Castro's response to the Varela Project, a proposed reform referendum.

"What's untouchable is liberty," Varela Project organizers said Tuesday about the government's proposed amendment.

Organizers submitted more than 11,000 signatures to Cuba's National Assembly on May 10, demanding a referendum asking voters if they favor civil liberties such as freedom of speech and assembly, the right to own a business, electoral reform and amnesty for political prisoners.

Most Cubans first heard of Project Varela in May when former U.S. President Jimmy Carter mentioned it in his television address to the Cuban people. Most Cubans still do not know what exactly the document proposes.

"We warn that this anticivic attempt against the same constitution, against the people's intelligence, is a very grave act against popular sovereignty," Project organizers Oswaldo Paya and Miguel Saludes said in a statement.

Copyright 2002 The Miami Herald