The European Union is set to extend economic sanctions against Russia until January to keep pressure on Moscow over the conflict in eastern Ukraine.

An EU diplomat said Wednesday that European ambassadors decided to prolong "the most serious package of our sanctions" before they expire next month.

EU foreign ministers must still endorse the move on June 22.

The diplomat said the sanctions include limits to access on some financial markets and a ban on certain technologies.

Trade and investment sanctions linked to Crimea and Sevastopol would be extended for one year.

The diplomat declined to be named because the ambassadors' deliberations are rarely made public.

Fighting between Ukrainian forces and Russian-backed rebels has killed more than 6,400 people and persists despite a cease-fire agreed in February.