At least two people were killed and 28 injured in a massive Russian drone attack on the Ukrainian city of Kharkiv, Mayor Ihor Terekhov said Wednesday.

The official said that 17 Russian drone attacks hit houses and buildings in Kharkiv, including a five-story residential building in the Slobidskyi district, where a massive fire broke out.

Authorities do not rule out a higher death toll, according to The kyiv Independent, as several people are feared to be buried under the rubble.

Ukrainian authorities are considering introducing temporary restrictions on mobile phone services amid Russia's use of cellular networks to gather intelligence during increasingly widespread drone attacks, according to deliberations by the Ukrainian parliament's defense committee.

Long-range Shahed drones are Iranian

Russian long-range drones, including Iranian-made Shaheds, are increasingly being fitted with prepaid Ukrainian SIM cards to collect and transmit critical data during flights, according to experts analyzing drone wreckage.

The latest drone attack on Kharkiv occurred just hours after the exchange of the second group of prisoners of war agreed upon in the second round of negotiations in Istanbul, according to the Russian Defense Ministry and Ukrainian President Volodymyr Zelensky.

This exchange, which includes wounded, seriously ill prisoners and prisoners under 25 years of age, took place after the one made on Monday between the two sides.

In neither case was the number of exchanged prisoners specified, nor the date of the next exchanges, which will be carried out in the "all for all" format, but not less than 1,000, as previously reported by the chief Russian negotiator, Vladimir Zelensky.