European Union leaders are discussing a new series of sanctions against Russia, including an oil embargo.

A proposal banning oil imports from Russia by year-end is among the items on the table at the two-day summit that kicked off in Brussels on Monday. The leaders are also looking at providing further support to Ukraine.

The embargo proposal has drawn strong opposition from Hungary, which receives oil from Russia through a pipeline. The country said the ban would threaten its energy security.

A high-ranking EU official said the leaders are aiming to reach an agreement on an embargo that targets seaborne oil imports only, and excludes pipeline-supplied oil. The official said Russian oil shipments to some member states may be sanctioned at a later point.

However, it remains to be seen whether the EU member countries will be able to narrow their differences over the sanctions package, which was proposed nearly four weeks ago in early May.

Some leaders struck a cautious note when speaking to reporters before the meeting. Hungarian Prime Minister Viktor Orban said they have not yet come to a solution.