MALÉ, MALDIVES (AFP) - An explosion ripped through a speed boat carrying Maldives President Abdulla Yameen on Monday, injuring his wife and two others but leaving him unhurt, a minister said.

It is not clear what caused the blast on the presidential craft as it docked in the capital island Male.

Authorities have launched an investigation, said Mr Mohamed Hussain Shareef, minister at the President's Office.

"The first lady Fathimath Ibrahim, a senior protocol officer and a bodyguard of the president were hurt and taken to hospital," Mr Shareef told AFP.

"The president was unhurt and he escorted the first lady to hospital where she is under observation following a minor injury."

Reporters were at the presidential jetty to receive Mr Yameen, who had landed a few minutes earlier at the nearby Hulhule airport after a visit to Saudi Arabia where he had performed the haj pilgrimage.

Witnesses said they saw an ambulance rush to the jetty and police immediately cordoned off the area.