Russia’s government declared flooding in the Orenburg region a federal emergency on Sunday, state media reported.

The floods, caused by rising water levels in the Ural River, have forced more than 4,000 people, including 885 children, to evacuate, the regional government said.

State news agency Tass said a further 2,000 homes were flooded, taking the total in the area to nearly 6,300.

Russia’s Emergency Situations Minister Alexander Kurenkov arrived in Orsk – one of the hardest-hit cities – on Sunday to supervise rescue operations.

“I propose classifying the situation in the Orenburg region as a federal emergency and establishing a federal level of response,” the minister said, according to RIA Novosti.

Orsk, less than 13 miles (20km) north of the border with Kazakhstan, suffered the brunt of the floods, which caused a dam to break on Friday, according to Orsk Mayor Vasily Kozupitsa.

By Sunday morning, 4,500 residential buildings in the city with a population of 200,000 were flooded and evacuation efforts were continuing, Tass said.

A criminal probe has been launched to investigate suspected construction violations that may have caused the dam to break.

Local authorities said the dam could withstand water levels up to 18ft (5.5). On Saturday morning, the water level had reached 30.51ft (9.3m) and was still rising, Mr Kozupitsa said.

On Sunday, the level in Orsk reached 31.82ft (9.7m), according to Russia’s water level information site AllRivers.

Officials in Orsk reported on Sunday that four people had died, but said their deaths were not related to the flooding.

Officials in the regional capital (also called Orenburg) some 155 miles (250km) away from Orsk, wrote on Telegram on Sunday that the situation in the city was “getting worse”, as water levels increased by 11.02in (28cm) compared with the previous day.

More than 1,300 homes were flooded and 428 people had been evacuated, they said.

Footage from Orsk and Orenburg showed water covering the streets dotted with single-storey houses.

The Ural River, about 1,509 miles (2,428km) long, flows from the southern section of the Urals into the north end of the Caspian Sea, through Russia and Kazakhstan.