U.S. Secretary of State John Kerry is in Ukraine aiming to reassure the former Soviet republic that the United States stands by it in its territorial disputes with Russia.

Kerry arrived in Kiev on Thursday, a day after making a similar visit to Tbilisi, where he signed an agreement to boost U.S.-Georgia military cooperation, sending a not-so-subtle message to Russia ahead of this week's NATO summit.

Kerry is meeting Ukrainian President Petro Poroshenko and others to discuss progress made on reforms called for by an agreement to end the conflict in eastern Ukraine with Russian-backed separatists.

Georgia and Ukraine are both deeply worried about Russian activities on their territory and have sought closer ties with the West, including association with the European Union and the prospect of NATO membership.