Ministers of the world's largest regional security body are to meet Thursday in Skopje as the 57-member organisation faces its most serious crisis since its creation with tensions from Russia's invasion of Ukraine remaining heightened.

The Organisation for Security and Co-operation in Europe (OSCE) has been struggling to survive as Russia is blocking decisions, such as the organisation's budget.

Created in 1975 as a forum for dialogue between the Eastern and Western blocs, the organisation -- of which both Russia and Ukraine are part -- has been operating with extra budgetary means, but tensions are running high.

Ukraine, as well as Estonia, Latvia and Lithuania have already said they would boycott the annual ministerial conference after the invitation of Russian Foreign Minister Sergei Lavrov, who said he plans to attend.

Poland joined the boycotters on Wednesday, with Foreign Minister Szymon Szynkowski vel Sek decrying Russia being "present at the table of the organisation that is supposed to build peace and security in Europe".

But the EU's top diplomat, Josep Borrell, said Wednesday that Russia needed to hear from ministers about why it is being "condemned and isolated".

He added the decision of North Macedonia, which currently holds the OSCE presidency, to allow Lavrov to participate aligned with the "common objective of keeping multilateralism alive".

US Secretary of State Antony Blinken is also attending the meeting to seek to rally support for Ukraine.

'NATO branch'

After months of negotiations, Malta agreed last week to take over the organisation's rotating presidency next year, instead of NATO member Estonia -- which Russia openly rejected.

The decision is expected to be ratified during the two-day ministerial meeting and avoids a collapse of the pan-European security body.

Blinken expressed gratitude to Malta for "stepping forward to assume the responsibilities of the chairpersonship" next year.

"Malta has the full support and confidence of the United States," he said on X.

On Wednesday, Russia accused Western countries of trying to prevent its officials from attending the ministerial conference. 

"We see attempts by part of the West to do everything possible to hinder our country's normal participation at this meeting," Russian foreign ministry spokeswoman Maria Zakharova said. 

She accused some countries -- without naming them -- of threatening "the very existence of the organisation, just to satisfy their ambitions."

"It is important to understand that the OSCE cannot be a branch of NATO and the EU," Alexander Lukashevich, Russia's representative to the OSCE, said in a September speech, adding it remained "one of the central elements of prevention" of a "large-scale military escalation in Europe".

Kyiv, in turn, wants Russia expelled from the OSCE as the Council of Europe did, warning the body faced a "slow death" if Moscow remained a member.

'Workarounds'

"It is a big challenge to keep the OSCE alive," Alexander Van der Bellen, president of Austria, which hosts the body's seat, told foreign correspondents this month.

It is increasingly difficult to keep human rights on the agenda -- given the consensus ruling the organisation is built on. 

An observation mission in Ukraine also packed up hastily last year after Moscow invaded its neighbour.

However, Michael Carpenter, the US ambassador to the OSCE, insisted the organisation was "finding workarounds" to show Russia's isolation and not let it "undermine its effectiveness".

"Although there are very, very serious challenges to the organisation right now... in fact, this organisation is delivering in many ways," he told journalists this month.

"We will not allow Russia to kill this organisation," he added.

Since the beginning of the war, the OSCE has issued several reports on possible war crimes and crimes against humanity Russian armed forces are accused of in Ukraine.

OSCE election observers also continue to be deployed to monitor polls around the globe.

The OSCE itself also insists on its relevance.

"The OSCE's role is now more important than ever and remains invaluable to so many people across the region," an OSCE spokesperson told AFP, citing the organisation's support to members to fight human trafficking and addressing climate change.