LUXEMBOURG—European Union foreign ministers extended broad economic sanctions on Russia until the end of January 2016, a move designed to give the bloc time to gauge if the Kremlin will fully implement its side of February’s Minsk cease-fire and peace plan by year-end.

The EU decision came without a debate among ministers, underlining that despite months of public questioning of sanctions by the likes of Greece and Hungary, the bloc remained united in opposing Russian pressure on Ukraine.

That unity will continue to be tested in coming months if the fragile cease-fire holds as pressure grows within the bloc to broaden dialogue with Russian President Vladimir Putin and his government.

EU officials have argued that the banking, technology and defense industry sanctions have had a significant impact in weakening Russia’s economy, helping to push the country into recession alongside a sharp drop in the oil price. The sanctions were due to expire at the end of July.

Critics say the policy has had no effect in forcing Moscow to re-examine its policies and is sowing a deep division between the EU and its eastern neighbor.