The European Union turned to Norway for gas last year as it scrambled to reduce its dependence on Russia after Moscow invaded Ukraine and cut deliveries to EU nations.

In a show of unity, Norway's Prime Minister Jonas Gahr Store met with NATO Secretary General Jens Stoltenberg and European Commission President Ursula von der Leyen on the Troll platform.

Store stressed the importance of protecting energy infrastructure in view of Russian energy "blackmail" and said Norway would be able to maintain its elevated deliveries to Europe for four to five years.

Located about 65 kilometres (40 miles) west of Bergen, Norway's second largest city, Troll is the country's largest gas field and one of its biggest oil fields.

It alone supplies the equivalent of 10 percent of Europe's gas consumption, as Norway has made up, at least in part, for the reduction in Russian supplies.

"In a more dangerous world, in a more unpredictable world, it's even more important that we stand together and ensure these kinds of extremely important infrastructure for our economies, for our daily life and also for our security," Stoltenberg told reporters.

Norway upped its gas production last year and now covers between 30 and 40 percent of Europe's needs.

Russian President Vladimir Putin "tried to blackmail the European Union by cutting us off Russian gas supply," European Commission President Ursula von der Leyen said, while lauding Norway for stepping up.

But the vital infrastructure is also vulnerable, as demonstrated by the September 2022 sabotage of the Nord Stream pipeline in the Baltic Sea.

NATO and the EU have set up a working group to strengthen the protection of their critical infrastructure, and a first meeting took place on Thursday.

Following a German-Norwegian request, the trans-Atlantic alliance also agreed to set up a coordination body for the protection of maritime infrastructure.

"Norway has about 90 offshore installations and 8,000 kilometres of pipelines, and it is a very good sign that NATO can take a responsibility," Store said.

Two Norwegian and German ships were patrolling near the platform on Friday, as well as maritime surveillance aircraft and a helicopter.