Israel has transferred 16 Bell AH-1 Cobra attack helicopters to Jordan to assist its air force in the fight against Islamic State militants, US sources have confirmed.

The rotorcraft involved had been phased out of use by the Israeli air force several years ago, and were refurbished prior to being flown to Jordan, the sources add.

Israel began operating AH-1s in 1975, and the type received several upgrades through its service with the nation. Since being replaced by more capable Boeing AH-64 Apaches, the aircraft had been in storage.

Foreign sources have claimed that Israel and Jordan have been cooperating in the fight against Islamic State, in most cases through joint intelligence activities. This is the first time that there has been a transfer of weapon systems between the nations, the sources add.

AH-1 - Israeli air force

Israeli air force

Israeli, Jordanian and US officials decline to comment on the move, which could only have been made with Washington's approval.

Flightglobal's Fleets Analyzer database records the Royal Jordanian Air Force as having 31 AH-1Fs in operational service, prior to any additions received from Israel.