(CNN) Two non-governmental organizations have said they are suspending migrant search and rescue operations in the Mediterranean because they feel threatened by the Libyan authorities.

Germany-based NGO Sea-Eye cited an "explicit threat" to humanitarian organizations from the Libyan government as it announced its decision Sunday in a statement on its official Facebook page.

"We decided with a heavy heart to temporarily suspend our planned rescue missions in the Mediterranean," the group's founder Michael Buschheuer said.

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

The announcement came a day after a similar decision was made by Doctors Without Borders, also known as Médecins Sans Frontières, or MSF.

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