The Philippines' presidential front-runner, Ferdinand Marcos Jr., has skipped a presidential debate organized by the country's election commission for the second time in a row.

The other nine candidates took part in the event held in the capital Manila on Sunday. The participants included Vice President Leni Robredo and Manila Mayor Francisco Domagoso.

The topics of the debate included diplomacy with China. The two countries have a territorial dispute in the South China Sea.

Marcos has been shying away from presidential debates, including the first one organized by the election commission and another by a broadcaster.

He restricts his public exposure to some media outlets. Observers say he may be trying to avoid tough questions.

A recent poll conducted by a political consulting firm shows Marcos leading the race with a 55 percent support rate, followed by Robredo with 21 percent and Domagoso with eight percent.

Marcos is the eldest son of former president Ferdinand Marcos, who ran the Philippines with an iron fist.

The Philippines will hold the presidential election on May 9 to decide who will succeed incumbent Rodrigo Duterte.