Several migrants are feared dead when a boat capsized between Malta and Libya on Easter Sunday, an NGO said.
At least four rubber dinghies with some 250 migrants on board were reported to be in distress to the south of Malta over the past few hours.
In a statement, Sea Watch said the migrants had been left to die on Easter, while Europe speaks about people's suffering.
It is so far unclear which vessel has capsized.
Both Italy and Malta have closed their ports to migrant vessels. Prime Minister Robert Abela has insiste that Malta cannot guarantee it will be able to carry out migrant rescues as all its military resources are deployed on Covid-19 containment measures.
Abela said the topmost priority is to safeguard the health of the Maltese people.
Alarm Phone said that the migrants onboard one of the boats said that they are all tired and two persons had passed out. "We do not know if they are alive or dead. We need water."
In another tweet, the group said the migrants do not have enough energy left to get the water out of the boat and that their phone battery was about to die.
"RCC Malta refuses to listen to us on the phone and hangs up."
A number of NGOs have urgently called on the Prime Minister to ensure that all persons within Malta's responsibility are rescued and that their safety is guaranteed.
"The nation cannot quietly celebrate Easter whilst men, women and children are drowning on our doorstep. Saving lives and ensuring their disembarkation at a safe place is a fundamental legal obligation and also a moral imperative that can in no way be negotiated or renounced," they said.
They also reiterated their previous message that Malta must revoke its decision to close its ports to persons rescued at sea, whoever they are.