Two fighter planes and their pilots were confirmed missing during a training session near Phu Quy Island in Binh Thuan Province on Thursday, Viet Nam News reported.

The jets, of Air Division 370, took off from Thanh Son Military Airport in Ninh Thuan Province Thursday morning and lost contact a few hours later.

According to Major General Do Minh Tuan, deputy commander of the Vietnamese Air Force, the jets’ expected crash area was 15km north of Phu Quy Island bordering Ninh Thuan and Binh Thuan provinces.

The Ministry of National Defence deployed forces for an urgent search immediately.

After hours of searching, rescuers found oil slicks and three of the jets’ oil tanks in the sea. Authorities suspected the pilots jumped out of the planes around 10:35am when the accident occurred, but they still haven’t been found.

The USSR-made Sukhoi Su-22 jets began serving in the Vietnamese Air Force in 1979.

Two VN fighter jets reported missing in Ninh Thuan - Thai PBS English News