Want climate news in your inbox? Sign up here for Climate Fwd:, our email newsletter.

ROVANIEMI, Finland — Secretary of State Mike Pompeo on Monday sharply warned China and Russia against “aggressive” actions in the Arctic, while resisting a diplomatic push by other countries in the region to avert the worst effects of climate change.

“This is America’s moment to stand up as an Arctic nation,” Mr. Pompeo said. “The region has become an arena of global power and competition.”

He was speaking at a meeting of the Arctic Council, an international organization made up of eight Arctic countries and representatives of the indigenous people of the area. The Council’s mission is to cooperate on Arctic issues, especially how to protect its fragile environment.

The Arctic is heating up far faster than the world average because of rising greenhouse gas emissions, scientists have warned. Over the past five years, the region has been warmer than at any time since 1900, when record keeping began.