The president of the Maldives was unhurt but his wife and two aides were injured in an explosion on Monday on board their launch as it approached Male, capital of the Indian Ocean archipelago, a senior aide told Reuters.
The cause of Monday's blast, witnessed by journalists who were waiting to meet President Abdulla Yameen on his return from the Haj pilgrimage to Saudi Arabia, was not clear.
Footage aired on television showed chaotic scenes as Yameen's staff tried to get the injured off the stricken launch onto a police boat as both bobbed on the waves by a jetty.
"There was a explosion at President Yameen's official speedboat near Male jetty. The president is unhurt, but the first lady was slightly injured," Mohamed Hussain Shareef, minister at the president's office, told Reuters.
Yameen, 59, is a controversial figure both at home and abroad. He rose to power in a bitterly contested presidential election in 2013.
The leader he defeated, Mohamed Nasheed, was jailed this year for terrorism in a case that has drawn international criticism. Human rights lawyer Amal Clooney called for international sanctions against the Maldives after visiting Nasheed this month.
A broader crackdown against political dissent belies the reputation of the Maldives as a holiday paradise, with radicalised youths enlisting in significant numbers to fight for Islamic State militants in the Middle East.
Yameen had landed earlier at the main international airport of the Maldives, an island chain with a population of 400,000, and was making the short journey to Male by water with his entourage.
"Investigations are ongoing. The starting point is that it could be an accident - possibly mechanical or an engine-related blast," said Shareef.
"But until they find it fully, nothing can be ruled out."
A Reuters witness saw Yameen walking and helping an injured victim soon after the explosion, which happened when his boat was just six feet (two meters) from the jetty.
His wife, Fathimath Ibrahim, fell as she emerged and was carried off the presidential boat by soldiers. A rear door was partly blown off its hinges in the blast.
Fathimath Ibrahim was evacuated to Male's main hospital to be treated for back injuries. A bodyguard who suffered multiple fractures was also taken to hospital, as was a protocol officer who suffered a limb injury, Shareef said. The presidential launch was maintained by the Maldives National Defense Force and investigators will check whether they followed security protocols, he said.