The Kremlin announced Thursday that humanitarian corridors to get civilians out of Mariupol's Azovstal steel plant were functioning, after the Russian army announced a three-day ceasefire at the site.

"The corridors are functioning today," Kremlin spokesman Dmitry Peskov told reporters, adding that the steelworks remained besieged by Russian forces.

Earlier, the Russian military has declared a fresh unilateral pause in its operation at the Azovstal steelworks complex in Mariupol, offering to provide humanitarian corridors for people who are believed to have been trapped within the site for three days.

The steel factory is the city's final stronghold controlled by the Ukrainian military and members of the neo-Nazi Azov battalion.

The humanitarian corridor will be available for three days, from Thursday to Saturday, from 8 AM to 6 PM Moscow time. Civilians evacuated from the facility will be able to move wherever they choose, including territory controlled by Ukraine or Russia.

Several hundred residents were evacuated from Azovstal bunkers on Sunday as part of a humanitarian mission coordinated by the United Nations and the International Red Cross.

Kremlin spokesman Dmitry Peskov explained that “There is no assault. We see that flare-ups occur when militants get out to assume gun emplacements. These attempts are being suppressed quite promptly."

The Kremlin denied on Wednesday that Russia was attacking the Azovstal steel mill in Mariupol after Ukraine accused Moscow of launching a "powerful" assault on the industrial zone where Kiev's military is stationed.

Russian Foreign Minister Sergey Lavrov said on Sunday that Ukraine's "hysterical" desire to take militants out of Mariupol's Azovstal plant is related to the fact that these militants can confirm the presence of active officers, as well as mercenaries, from Western armies.