Investigators said they were questioning the pilots of the Sukhoi Su-34, who managed to parachute out of the plane before it crashed on Monday into the nine-storey building, engulfing it in flames.

Nineteen people were injured, four of them critically.

The crash was probably caused by "a technical malfunction", Russia's Investigative Committee, which probes serious crimes, said.

It said it had launched a criminal inquiry into possible violations of flight rules, and had "seized fuel samples at the departure aerodrome" and "flight recorders at the site of the crash".

Russia's defence ministry said the jet collided with the block, which was home to around 600 people, during a training flight.

"The pilots who managed to eject, as well as the airfield personnel, are being questioned," the investigators said.

On Tuesday, when the ministry of emergency situations said rescuers had ended their search for survivors in the rubble, the southern seaside town near the border with Ukraine was in shock.

- Putin 'expresses deep condolences' -

Grieving locals left flowers and children's toys to a makeshift memorial near the residential building, where a black board read "Yeysk. 17.10.2022. We remember. We mourn."

They placed red roses, candles and smiling teddy bears around the board, in memory of the three children killed by the crash.

Officials said four people, including a five-year-old girl and a teenage boy, were in critical condition and had been taken for treatment to regional hub Krasnodar.

The Kremlin said Tuesday that President Vladimir Putin "expresses deep condolences to those families who lost their loves ones as a result of this disaster."

Images of the dramatic crash showed the burnt-out fuselage of the plane, which snapped in two on impact.

One of its mangled wings bore a red star -- the symbol of the Russian army.

The remains of wrecked parked cars littered the foot of the building, trapped when the blaze engulfed at least five of its floors.

Yeysk, a city of around 85,000, lies on the Sea of Azov. A narrow gulf separates it from southeastern Ukraine and the Russian-controlled city of Mariupol.