Ukrainian President Volodymyr Zelenskyy has spoken with the leaders of Canada, the UK, and other nations to discuss boosting his country's defenses against Russia.

Zelenskyy held a series of phone talks on Tuesday with Canadian Prime Minister Justin Trudeau, British Prime Minister Rishi Sunak, and other leaders. The talks come amid intensifying attacks by Russia on Ukraine's eastern front.

Later, Zelenskyy released a video message thanking the countries for their support. He said Ukraine needs to strengthen its defenses in readiness for "new mobilization processes being prepared by the terrorist state."

Russian forces have launched a wave of heavy attacks on Ukraine in recent weeks, but they have also suffered losses. Dozens of soldiers were killed last weekend in a rocket attack on Russian barracks in Makiivka, adjacent to the regional capital of Russian-occupied Donetsk.

Russia's defense ministry initially said 63 soldiers were killed. It later raised the death toll to 89.

The ministry blamed the attack on the unauthorized use of mobile phones by its troops, which it said had allowed Ukrainian forces to track the coordinates of the users.