BELGRADE, Serbia (AP) — A senior European Union official has urged Serbia, a candidate for EU membership that is also Russia's key ally in Europe, to keep up its bid to join the bloc.

European Council president Donald Tusk said Wednesday in Belgrade that the EU "is and wants to remain the most reliable partner of Serbia and the Western Balkans," a region aspiring for EU where Moscow traditionally is vying for influence.

Tusk visited Belgrade as part of his week-long tour of Western Balkans to prepare for the May 17 summit of EU and regional leaders. Tusk spoke in Serbian after meeting President Aleksandar Vucic.

He said that "the future of Serbia won't be decided in Moscow or Washington, Ankara or Brussels." He describes the EU as a "project with a strategic dimension."