Ukrainian presidential adviser Oleksiy Arestovych has said that after a "risky maneuver" the last remaining defenders of the besieged port city of Mariupol have been able to join forces.
Arestovych said Wednesday that "in Mariupol, as a result of a risky maneuver, units of the 36th Independent Marine Brigade broke through to [join] the Azov regiment."
Both units have been involved in a last-ditch attempt to resist a Russian offensive against the city that has lasted well over a month.
"This is what happens when officers do not lose their heads, but firmly maintain command and control of the troops," Arestovych said.
CNN cannot independently confirm the details of the operation. Members of the Marine unit posted a video statement on Tuesday saying they would hold on "until the end," despite being surrounded by Russian forces and running low on supplies.
On his Facebook account, Arestovych said that the Azov regiment had "received substantial reinforcements ... the 36th brigade avoided defeat and received additional serious opportunities, in fact, gained a second chance."
Arestovych claimed that "the defenders of the city, now together, seriously strengthened their defense area."
The defenders of the city, where some 100,000 civilians remain trapped amid widespread devastation, have been fighting to hold parts of the port and Azovstal, a giant steel factory that lies on Mariupol's eastern outskirts.
The Russian military claimed in a statement Wednesday that 1,026 Ukrainian Marines -- including 162 officers and 47 women servicemembers -- had surrendered in the vicinity of the Ilyich Iron and Steel Works in Mariupol, a claim that could not be verified.
Russia has focused an intense propaganda effort around the battle for Mariupol, claiming to have seized key positions in the city, even as Ukrainian forces have continued to hold out.
Some background: Independent analysis of the situation in Mariupol on Sunday published by the Institute for the Study of War assessed that the defense of Mariupol had reached a critical stage.
Ukrainian President Volodymyr Zelensky has said "tens of thousands" have died in Mariupol, a figure that cannot be independently verified.