PANAMA CITY, Panama (AP) _ The three top opposition leaders defied a ban on rallies and marched through the streets on Saturday, their first public appearance since they were attacked and beaten 10 days ago.

Presidential candidate Guillermo Endara and vice presidential candidates Ricardo Arias Calderon and Guillermo Ford were assaulted by paramilitary forces supporting Gen. Manuel Antonio Noriega on May 10.

That was the day the government, controlled by Noriega, the Defense Forces chief, annulled the May 7 election.

Independent observers say the opposition candidates were leading the Noriega-picked government candidates in the national election when Noriega's troopers seized election ballots.

The government on Saturday prohibited ''marches, meetings, public demonstrations or caravans of vehicles'' by any political organization until at least June 5.

''The prohibition does not have any meaning to us,'' Endara said as he wended through an outdoor market on this capital's eastern outskirts. The stop was one of six made by a caravan of about 20 vehicles.

The motorcade briefly blocked traffic on some major arteries leading into the capital. Police watched but took no action.

At one point the candidates met with Rep. John Murtha, D-Pa., who headed a delegation named by President Bush to observe the May 7 election. The delegation claimed Endara won the election.

In a departure statement at the Howard Air Force Base, Murtha said he had returned to Panama Saturday morning to inspect conditions at American bases, confer with U. S. Embassy officials and meet with opposition leaders and Archbishop Marcos McGrath, the Roman Catholic primate of Panama.

Murtha, a member of the House Intelligence Committee, indirectly urged the Panamanian Defense Forces to move against Noriega.

President Bush ''is not interested in punishing the PDF,'' Murtha said. ''He is interested in dealing with the PDF. The target of our dismay is the leader of the PDF.''

Murtha refused comment when asked if he had spoken to any Defense Forces officers.

Endara said the caravan was designed ''to thank the people for their support May 7.''

Ford said the action was intended ''to reconstruct the confidence of the people in order to make another push.''

The tour had all the trappings of a classic campaign swing, with much kissing of babies, hand-pumping and shouts of ''Viva nuestro presidente 3/8'' or ''Long live our president 3/8''

A vendor at the Rio Abajo market shouted of Endara: ''He's the true president of Panama 3/8''

The Ministry of Government and Justice issued a communique saying the prohibition on demonstrations was in response to the imminent visit by delegates from the Organization of American States.

The foreign ministers of Ecuador, Guatemala, Trinidad and Tobago, accompanied by OAS Secretary-General Joao Baena Soares, are due in Panama on Tuesday. They will try to promote resolution of Panama's 15-month-old government crisis.

The organization on Wednesday approved a resolution critical of Noriega.

The government said the prohibition of political street activity was imposed to comply with the clause in the OAS resolution calling on ''the authorities and all political forces in Panama to abstain from any measure or action that could aggravate the crisis.''

The United States has been trying to oust Noriega since February 1988, when he was indicted on drug trafficking charges in Florida. Noriega has survived economic sanctions and international pressure, accusing the United States of seeking to scrap a treaty that will give Panama full control and supervision of the Panama Canal by the end of the century.

-20-89 2006EDT