The spokesman for the U.N. secretary-general says the situation with dozens of peacekeepers detained or restricted in movement in Syria remains "very, very fluid" as talks aimed at their release stretched into a second day.

Stephane Dujarric told reporters on Friday that some radio contact has been made with the 72 peacekeepers from the Philippines who have been restricted in movement. Another 44 peacekeepers from Fiji remain detained.

The U.N. has not said exactly who is holding the peacekeepers, whose mission monitors a 1974 disengagement accord between Syria and Israel.

Dujarric says the peacekeepers are being held by "non-state armed actors" who identify as the al-Qaida-linked Nusra Front.

He says talks continue "with a wide range of parties within Syria" and U.N. member states who may have influence with them.