SKOPJE, North Macedonia (AP) — A senior U.S. envoy launched a tour of several Balkan nations Wednesday, a visit focused on international efforts to help normalize relations between Kosovo and Serbia after weeks of heightened tension.

U.S. State Department Counselor Derek Chollet began the trip with a brief stop in North Macedonia and plans to travel on to Kosovo and Serbia.

The arrest in Kosovo of a former Serbian police officer triggered protests and road blockades by ethnic Serbs in the north of the country. Serbia's president talked about sending troops into Kosovo.

The United States supports longstanding European Union efforts to mediate the relations between Serbia and Kosovo, a former Serbian province that declared independence in 2008. Belgrade does not recognize Kosovo as a sovereign state.

The western diplomatic initiatives have taken on increased urgency over fears for the stability of the region following Russia’s invasion of Ukraine nearly 11 months ago.

In North Macedonia’s capital, Skopje, Chollet met with Prime Minister Dimitar Kovachevski but made no remarks after their talks.

The government said the discussion was focused on anti-corruption efforts, a key condition for North Macedonia’s bid to join the EU.

A tiny landlocked country of some 1.8 million people, North Macedonia started accession talks with the EU in July.