Canada is against the use of cluster munitions that Washington has promised to give Ukraine for its counteroffensive against occupying Russian forces, Ottawa said on Saturday, reiterating a commitment to the Oslo agreement that bans the controversial weapon.

The US said on Friday that it would supply Kyiv with the widely banned bombs as part of a new $800 million security package that brings total US military aid to more than $40 billion since Russia's February 2022 invasion of Ukraine.

Ukraine has welcomed the US decision, saying it would help liberate Ukrainian territory, but promised the munitions would not be used in Russia.

Cluster munitions typically release large numbers of smaller bomblets that can kill indiscriminately over a wide area. Those that fail to explode pose a danger for decades after a conflict ends.

"We do not support the use of cluster munitions and are committed to putting an end to the effects cluster munitions have on civilians – particularly children," the Canadian government said in a statement.

Another US ally, Germany, and UN Secretary-General Antonio Guterres have expressed their opposition to the US sending cluster munitions to Ukraine.

The bombs are prohibited under the Convention on Cluster Munitions, which was opened for signature in Oslo in 2008. While more than 100 countries are signatories, Russia, Ukraine and the United States have not signed on to the Convention, which bans production, stockpiling, use and transfer of the weapons.

"Canada is fully compliant with the Convention and we take seriously our obligation under the Convention to encourage its universal adoption," the federal government said in the statement.

The Liberal government of Prime Minister Justin Trudeau is one of Ukraine's most vocal supporters, and has committed billions of dollars in financial, military, humanitarian and other assistance since last year.