Canada and the US dismissed Russia's flag-planting at the North Pole on Thursday, with Ottawa calling it a "15th century" stunt that does not bolster its disputed claim to the resource-rich Arctic.
"Look, this isn't the 15th century. You can't go around the world and plant flags and say: `We're claiming this territory,'" Canadian Foreign Minister Peter MacKay told broadcaster CTV.
Washington said Russia's move to plant its flag on the seabed under the North Pole has no bearing on claims for rights to the mineral-rich subaquatic territory.
"I'm not sure of whether they've put a metal flag, a rubber flag or a bed sheet on the ocean floor," said State Department spokesman Tom Casey, in response to news that Russia had deposited a banner of rust-proof titanium as a symbol of its right to a vast expanse of the Arctic floor.
"Either way, it doesn't have any legal standing or effect on this claim," Casey said.
The spokesman added: "It certainly to us doesn't represent any kind of substantive claim, and I certainly haven't heard anyone else make the argument that it does."
The reactions came after six Russian explorers successfully descended to the ocean floor in two Mir mini-submarines to plant the flag.
Billed as the first successful expedition to reach the ocean floor under the North Pole, the explorers hope to establish that section of seabed as an extension of Russia's landmass.
But the claim has been greeted with derision in much of the world, including in Washington.
Casey noted that Russia's claim is based on its role as a signatory to the Law of the Sea Treaty, and observed that the US has not yet signed the agreement.
Even under that accord, Russia's case was thin at best, he said.
"This is a claim that I understand is based on their attempt to prove that certain underwater ridges really represent the outline of their continental shelf," Casey said.
"That's an issue that's going to be decided based on the technical merits, not on any kind of particular markers laid down."
Russia has said its expedition is scientific in nature, focusing on climate change questions in the polar regions.
But the effort also supports its claim, dating back several years and already submitted to a technical body under the Law of the Sea Convention, that its continental shelf extends beyond the generally accepted 200-nautical-mile (370km) limit.
"There are some fairly technical arguments that they've made," Casey said.
But the State Department spokesman added, "I don't think that ... whether they went and spray-painted a flag of Russia on those particular ridges is going to make one iota of difference."