The European Commission on Monday extended by six months to June 2024 a scheme enabling EU countries to help companies hit by energy price spikes caused by Russia's war on Ukraine.

The temporary measure allows the EU's 27 member states to grant various forms of financial aid to compensate firms impacted by high gas and electricity costs.

The scheme was introduced one month after Moscow's invasion of its pro-Western neighbour in February 2022 roiled energy supplies and helped send prices spiralling.

It was due to expire on December 31, 2023.

Although prices have stabilised since last year, the commission said "energy markets remain vulnerable".

"Member States can maintain their support schemes to cover the upcoming winter heating period as a safety net," it said in a statement.

But Brussels stipulated that subsidies are allowed "only as far as the energy prices significantly exceed pre-crisis levels".

The EU usually strictly controls state aid to firms in order to avoid distorting competition and to protect the bloc's single market.