U.S. Secretary of State John Kerry says Russia could rebuild its relations with the West if it simply helps calm the violence on its border with eastern Ukraine, where pro-Moscow separatists are fighting with Kiev forces.

Kerry was at a meeting Thursday of the Organization for Security and Cooperation in Europe, which includes both the United States and Russia as partners.

OSCE has sought to help broker an enduring cease-fire in eastern Ukraine, where it's believed Moscow is supporting the separatists with weapons and troops in their quest to secede from Ukraine's central government.

Kerry says Russia must uphold a cease-fire agreement it committed to months ago, which calls for withdrawing its support for the separatists and persuading them to release their hostages.