BRUSSELS - European Union countries reached an initial agreement on what would be the bloc's eight round of sanctions against Russia for waging war against Ukraine, three diplomatic sources told Reuters on Friday.

The EU executive earlier this week recommended that the bloc imposes more trade curbs and individual blacklistings and moves towards - rather than adopting straight away - a price cap for Russian seaborne oil deliveries to third countries, mostly insured by European companies.

The 27 EU countries' national envoys to Brussels discussed the proposal on Friday and gave their initial green light, with a final approval expected next week, said the three sources.

The 27 need unanimity to impose sanctions and, should their differences prove too difficult to overcome, the matter would go to the bloc's national leaders meeting in Prague on October 6-7, said the sources who all spoke under condition of anonymity.

Hungary is the most vocal critic of sanctions against Russia in the EU, which was galvanised by Moscow's fresh escalation in the seven-month war: military mobolisation, nuclear threats and moving to formally annex a large part of occupied Ukraine.

(Reporting by Gabriela Baczynska, Philip Blenkinsop)