Warplanes from a Saudi-led coalition bombed Yemen's presidential palace in the center of the Houthi-controlled capital Sanaa early on Monday, killing at least six people, Houthi-run media reported.

There was no immediate comment from the coalition, which entered Yemen's war in 2015 to push back Houthi fighters who had taken over large parts of the country, seized the capital and forced the government into exile.

Two air strikes damaged the palace as well as houses and businesses nearby in the city's central Tahrir district, the SABA news agency reported.

Abu Dhabi-based Sky News Arabia said two Houthi leaders, including Mohammed Ali al-Houthi, the head of the group's supreme revolutionary committee, were inside the palace at the time, but did not say what happened to them.

The Houthi-run Al Masirah TV said at least six people were killed and more than 30 wounded in the strikes.

Reuters could not independently confirm the reports.

Photos and television footage showed a building reduced to a pile of smashed concrete and twisted metal bars. An armed Houthi fighter tried to stop people approaching the site.

The two sides in Yemen have fought to a stalemate after more than three years of war.

Saudi Arabia and its allies have accused their rival Iran of arming and supporting the Houthis - an assertion dismissed by both the armed group and Tehran.

The Houthis say they are fighting for Yemen's sovereignty against a Western-backed plot to dominate the country.

A Saudi-led coalition airstrike last month killed the Houthis' top civilian leader in Yemen, Saleh al-Samad, the most senior official to be killed by the alliance.