© Antonio Parrinello / Reuters
Three NGOs have suspended migrant search and rescue operations in the Mediterranean citing threats from the Libyan Coast Guard, leaving what they describe as a "deadly gap" in the area.

Doctors Without Borders (MSF) said it would suspend search and rescue activity of its ship, 'Prudence,' saying on Saturday that the vessel would cease operations because of "hostility" from Libya.

Save the Children and Sea Watch on Sunday also suspended their ongoing rescue operations in the Mediterranean over the same safety fears.

Libyan authorities announced a new search and rescue zone off its coast earlier this week, which MSF says extends into international waters.

Libya has restricted the access of humanitarian vessels carrying out rescues in international waters, as part of a bilateral attempt with Italy to control the flow of illegal migration across a Mediterrenean channel between the two countries.

MSF said the Italian Maritime Rescue Coordination Centre (MRCC) warned the NGO of the security risks associated with threats made by the Libyan Coast Guard to search and rescue vessels.

"European states and Libyan authorities are jointly implementing a blockade on the ability of people to seek safety," Brice de le Vingne, MSF's director of operations, said. "This is an unacceptable assault on people's lives and dignity."

MSF's Loris De Filippi told Reuters the Libyan Coast Guard demanded the NGOs leave an area as big as hundreds of kilometers around its coast, where it had previously been allowed to carry our search and rescue.

Catalan NGO Practiva Open Arms accused the Libyan Coast Guard of firing warning shots at its boat and threatening the crew last week.

Sea Watch's founder, Michael Busch Heuer, announced it would suspend its rescue missions and accused Libya of issuing an "explicit threat" against NGOs in the area.

"The reason for this is the changed security situation in the Western Mediterranean, after the Libyan government announced an indefinite and unilateral extension of their territorial waters - in connection with an explicit threat against the private NGOs," Busch Heuer wrote on Facebook on Sunday.

"Under these circumstances, a continuation of our rescue work is not currently possible. It would be irresponsible towards our crews," he added.

Italy began training and supporting the coast guard of the UN-backed Libyan government in Tripoli last week, in an effort to increase its ability to intercept migrant boats and send them back to Libya.

The Tripoli government is one of three claiming authority in the country, and its power is disputed by other rival groups in Libya.

Italy's government has welcomed Libya's decision to prevent NGOs from entering its waters, having previously suggested NGOs are in fact colluding with people smugglers to rescue migrants.

"This sends a signal that the balance is being restored in the Mediterranean," Italian Foreign Minister Angelino Alfano saidSunday.

Italy has struggled with the wave of refugees and migrants arriving at its coast. Reuters reports close to 600,000 migrants arrived in Italy over the last four years.

"If humanitarian ships are pushed out of the Mediterranean, there will be fewer ships in the area to rescue people from drowning," Annemarie Loof, MSF's operational manager, said.

"Those who will not drown will be intercepted and brought back to Libya, which we know is a place of lawlessness, arbitrary detention and extreme violence."