A merchant ship has supplied fuel and water to a boat with around 400 migrants on board which is in distress between Greece and Malta but Maltese authorities have ordered it not to conduct a rescue, German NGO Sea-Watch International said on Monday.
The vessel, which departed from Tobruk in Libya amid a sharp rise of migrant boats crossing the Mediterranean from North Africa, was reported to be adrift and taking on water by support service Alarm Phone early on Sunday.
Alarm Phone said the boat was in the Maltese Search and Rescue area (SAR).
Sea-Watch International, which located the boat with one of its two planes, on Monday accused Malta of not wanting to rescue the people on board despite them being in serious danger and the vessel struggling with 1.5 meter waves.
"If the boat keeps moving, it might reach Italy and Malta does not have to accept the people," it said on its Twitter account.
Maltese authorities did not respond to several requests for comment.
In a separate episode, at least 23 Africans were missing and four died on Saturday after their two boats sank off Tunisia as they tried to reach Italy.
Last week 440 migrants were rescued off Malta after a complex 11-hour operation in stormy seas by the Geo Barents vessel of the Doctors Without Borders (MSF) charity.
According to press agency ANSA, on Sunday almost 1,000 migrants arrived in the Italian island of Lampedusa, south of Sicily.
(Reporting by Giulio Piovaccari; additional reporting by Christofer Scicluna in Valletta; writing by Giulio Piovaccari; Editing by Toby Chopra and Barbara Lewis)