Norway will come under France’s nuclear umbrella, Prime Minister Jonas Gahr Stoere told news agency NTB on Wednesday, as concerns grow in Europe over U.S. commitment to the region’s security.

The move by Norway is significant as it has long been a so-called Atlanticist nation, one which believed its security was best achieved via close alignment with Washington.

Stoere travelled to Paris on Wednesday afternoon to meet President Emmanuel Macron and sign a new defence agreement with France, which includes Norway joining a French-led nuclear weapons initiative.

“We are doing this in light of the security policy situation in Europe, including Russia’s massive rearmament, also in the nuclear domain, and that it is waging a full-scale war against another European country,” Stoere told Norwegian news agency NTB.

No nuclear weapons will be deployed in Norway in peacetime, he added.

The Nordic nation of 5.6 million inhabitants is a member of NATO, but not of the European Union, and shares a border with Russia in the Arctic.

In March, France offered to extend the protection of its nuclear umbrella to other European countries which, in practice, means that an attack on Norway could trigger a French nuclear response.

Norway becomes the latest country to receive France’s nuclear protection, after Poland and Lithuania, which also share borders with Russia.

Russia and the U.S. are the world’s biggest nuclear powers, with over 5,000 nuclear warheads each. China has about 500, France has 290 and Britain 225, according to the Federation of American Scientists.