Ukrainian President Volodymyr Zelensky has accused European allies of seeking to "blackmail" Kyiv into reopening a pipeline transporting Russian oil to Hungary and Slovakia.

He said restoring the flow of Russian crude oil through Ukraine into the European Union (EU) would be like lifting economic sanctions on Moscow.

Ukraine says the Soviet-era Druzhba oil pipeline was damaged by Russian air strikes in January and has yet to be repaired.

Hungary depends on Russian energy and is blocking both fresh EU sanctions on Moscow and a vital €90bn ($103bn; £78bn) loan for Kyiv until the pipeline is reopened.

Hungarian Prime Minister Viktor Orban has made hostility towards Ukraine a key issue ahead of April elections. His party is entering the race trailing behind in opinion polls.

The EU has urged Zelensky to repair the pipeline quickly and is asking him to allow inspectors in to visit the damage. Some EU officials fear Zelensky's resistance may help Orban win re-election.

But talking to reporters in Kyiv, including the BBC, Zelensky said he was simply opposed in principle to allowing Russian oil to transit through Ukraine while the EU sanctioned its sale elsewhere.

He said: "We either sell Russian oil or we don't. Because [the EU] are forcing me to restore Druzhba.

"How is this different from lifting sanctions on the Russians? Why can we in one case tell the United States that we oppose lifting sanctions, while on the other hand forcing Ukraine to resume oil transit through Druzhba – and at a political price that effectively pays for anti-European policies?"

Zelensky's comments come after the US loosened sanctions preventing other countries buying Russian oil in order to ease the energy supply crunch sparked by the US-Israel war with Iran. The move has drawn criticism from a number of European leaders.

"If we have decided to restore Russian oil supplies, then I want them to know that I am against it. And there is no need to accuse me of blocking anything. I am not blocking it," Zelensky said.

"I am saying openly: I am against it. But if I am given conditions that Ukraine will not receive weapons, then, excuse me, I am powerless on this issue. I told our friends in Europe that this is called blackmail."

He added that the EU decision to loan Ukraine €90bn had been adopted by all 27 countries and must be implemented.

Talking about the widening conflict in the Middle East, Zelensky described his country's interceptor drones as "Ukrainian oil" and said he was ready to agree a $50bn joint production deal with the US.

He said the US had "reached out to us several times" and claimed Washington was "very interested" in a deal.

Since that war broke out, many countries - especially in the Gulf - have asked Ukraine for help defending against cheap Iranian-designed drones.

Ukraine is a world leader in both producing cheap interceptor drones but also in learning how best to use them against almost nightly Russian attacks.

"For us, this is like oil," Zelensky told reporters. "The production of modern drones and Ukraine's relevant expertise is our today's Ukrainian oil."

He emphasised that Ukraine would want both money and technology in return for any agreements.

He added that Ukraine had proposed a joint production drone deal with the US last year but it had not been agreed.

"We were ready then, and are still fully ready now. We would welcome such a shared use of experience. That is why we made this proposal," he said.