Thousands of protesters formed a river of white as they marched around a lake in a Los Angeles park Sunday, joining other marchers around the world to expose the plight of political dissidents in Cuba and support the wives, mothers, and other women who defend them.

Before the procession at Echo Park northwest of downtown Los Angeles, a crowd estimated at 3,000 to 5,000 heard speeches by actor Andy García, comedian George Lopez, celebrity blogger Perez Hilton, and others.

``You have to look at human rights in Cuba,'' García told the throng.

``It has been ignored for 50 years. The Castro brothers have been in control of the information, but with technology, blogs, and Tweets they have lost control and people are now in the streets,'' said García, who was born in Cuba and grew up in Miami-Dade.

The Los Angeles demonstration was one of several marches during the weekend, from New York City to Madrid. They followed in the footsteps of the tens of thousands who walked Thursday down Calle Ocho in Miami, led by Cuban-American musical icon Gloria Estefan.

`VERY HUMAN CAUSE'All sought to show solidarity with the Ladies in White -- Las Damas de Blanco -- who have protested in silence in Cuba since the 2003 jailing of 75 Cuban dissidents, and who were violently confronted by government security forces earlier this month.

March organizers said their goal was simple: to show that human-rights abuses in Cuba are a worldwide issue.

``This is not about politics. It is a very human cause,'' said Sean McKean, whose mother is from Cuba. McKean helped organize a silent march in New York on Sunday with a national network of Cuban-American youth, called Raíces de Esperanza (Roots of Hope).

Under gray skies and intermittent chilly rain, the New York event started small. But it quickly drew hundreds who marched down Fifth Avenue to the statue of Cuban hero José Martí at the southern end of Central Park.

Yale University professor and author Carlos Eire said he joined the New York protest because the world has ignored the Ladies in White, whom he compared to South Africa's Nelson Mandela.

``Their men, their fathers, their brothers who are in prison are suffering the same kind of discrimination,'' Eire said.

Earlier Sunday, more than 50 people -- including poet María Elena Cruz -- gathered in front of the Cuban Embassy in Madrid in support of the Ladies in White, according to Spanish media reports.

And in Cuba, blogger Yoani Sánchez said via the micro-blogging website Twitter that 25 Damas de Blanco demonstrated Sunday in Havana's Miramar district.

``There have not been any interruptions,'' Sánchez wrote on Twitter.

ONE INCIDENTIn Los Angeles, however, there was one ruckus when a man stood on a hill overlooking the crowd and waved a Cuban flag with an image of Che Guevara, the Argentine who helped lead the Cuban Revolution.

The crowd booed and organizers urged them to stay calm.

``We have the freedom to do that in this country,'' Hilton said, drawing cheers.

But later a band of men clad in white wrestled the flag away and stomped it into the ground.

The demonstrations in Los Angeles and New York drew families, exiles who had not seen their homeland for decades, political prisoners like Huber Matos, and youths who were born in the United States. Gladiolas, white roses, flags, and banners dotted the crowd in Los Angeles.

One sign read: ``A black American asked for a change and became U.S. president. A black Cuban asked for a change and Castro put him in jail.''

For many, the marches for the Ladies in White renewed their hope for change.

``We hope this will be the spark to help the Cuban people who have suffered for 51 years,'' said Alberto Montero, 71, who came to the United States in 1963 and joined the Los Angeles march.