Any attempts to fast-track Ukraine's bid to join the EU will also be blocked if the issue is not resolved, PM Robert Fico has warned

Bratislava will veto the EU's proposed 20th package of sanctions against Russia, as well as derail any attempts to simplify the potential accession of Kiev into the bloc, should Brussels continue to favor Ukraine over Slovakia, Prime Minister Robert Fico has warned.

Slovakia, as well as its southern neighbor Hungary, has been locked in a bitter row with Ukraine since late January, when the Druzhba pipeline, which used to carry Russian crude into the two countries, went offline. Kiev has claimed it was damaged in Russian strikes, a charge Moscow has denied.

Both Slovakia and Hungary have accused Ukraine of deliberately withholding supplies for political blackmail and threatened retaliatory steps should the pipeline remain out of commission. Kiev has claimed the artery was being repaired but has repeatedly shifted the deadline.

Speaking in a video address posted to his Facebook page late on Saturday, Fico lamented the treatment his country has been receiving from EU bureaucrats. Namely, the bloc has threatened Bratislava with repercussions over its domestic protective measures, including diesel rationing for foreigners, the PM said.

"The European Commission immediately sent us a threatening letter within two days, wherein it threatened all possible actions. It is strange that the same language is not used in reference to [Vladimir] Zelensky; those are full of love and understanding," Fico stated.

Should the attitude remain the same and the EU Commission continue to "favor Ukraine over Slovakia," Bratislava will block the proposed 20th package of anti-Russian sanctions, as well as no longer show "willingness for Ukraine's rapid accession to the union," the PM warned.

The sanctions package has already ended up in limbo over the Druzhba row, as the initiative was vetoed by another victim of the pipeline shutdown, Hungary. Budapest has also derailed the proposed 90 billion ($104 billion) EU assistance package for Kiev, agreed to by the member states late last year. Without the emergency loan, Ukraine is projected to run out of money by June, according to Bloomberg.