U.S. warns Russia on sticking to Ukraine ceasefire accord

WASHINGTON (Reuters) - The United States said on Monday it would be ready to "increase the costs" to Russia if it fails to comply with the terms of ceasefire agreements with Ukraine, suggesting potential further economic sanctions on Moscow.

In a meeting with Ukraine's finance minister Natalia Yaresko, U.S. Treasury Secretary Jack Lew said the United States would take action if Russia continued to undermine Ukraine's sovereignty and stability.