EU foreign-policy chief Federica Mogherini has urged Kosovo’s political opposition to ratify a border-demarcation agreement with Montenegro, the last remaining hurdle before it can benefit from visa-free travel to Europe’s Schengen zone, RFE/RL reports.

Mogherini on March 4 met with senior officials in Kosovo’s capital, Pristina — the last stop on her tour of the Western Balkans.

She commended Kosovo’s leaders for their “constructive stand” in lowering recent tensions with Serbia.

“It’s time to vote for the ratification of the agreement. That would release the visa liberalization for the Kosovo people,” she said at a news conference with Prime Minister Isa Mustafa.

Mogherini urged opposition political parties to renounce their political interest “and work together for the reconciliatory path to take the country ahead.”

The country’s opposition has prevented parliament from voting on the border agreement with Montenegro, and another deal with Serbia that gives more powers to ethnic Serbs in Kosovo.

Mogherini last month summoned Kosovo’s and Serbia’s presidents and prime ministers twice to Brussels.

She offered reassurance that the European Union’s doors remain open for enlargement, although the Western Balkan countries are at different stages of integration into the bloc.

On March 3, Mogherini met with senior Albanian officials and political leaders in Tirana. She reminded them that reforming the justice system and holding free elections were two conditions required for the launching of full EU membership negotiations.

Mogherini’s warnings came as hundreds of supporters of Albania’s main opposition Democratic Party kept blocking the main thoroughfare in Tirana, saying they don’t trust the left-wing government to hold the June 18 parliamentary elections in a fair manner. They want a caretaker cabinet instead.

Albania was granted EU candidate status in 2014.