European Union foreign ministers are discussing how they can help implement a U.N. plan to freeze fighting in the northern Syrian city of Aleppo.

The EU's foreign affairs chief, Federica Mogherini, said she hopes the ministers can agree on "concrete" ways to help at a meeting Monday in Brussels.

The foreign ministers met informally Sunday with the U.N. special envoy to Syria, Staffan de Mistura. The U.N. has been trying to bring about a strategic de-escalation of violence in Syria to permit the delivery of humanitarian aid and set the stage for peace talks.

The ministers will also meet with Ukraine's prime minister, Arseniy Yatsenyuk, for the first meeting of the EU-Ukraine Association Council, a new step in the bloc's relations with Ukraine.