A Saudi Arabian government adviser says the kingdom has imposed a naval blockade on northern Yemen's Red Sea coast to try to prevent weapons and fighters flowing to Shiite rebels in the area.

The adviser said Tuesday that Saudi warships were ordered to search suspicious ships sailing near northern Yemen. He spoke on condition of anonymity because he was not authorized to speak to the media. Saudi-owned Al-Arabiya television also reported the blockade.

Both Yemen and Saudi have accused Iran of sending weapons and money to the rebels, who have been fighting Yemen's government for the past five years.

Iran denies the charge, and it sternly warned Yemen's neighbors Tuesday not to interfere in the country's internal affairs.