NATO: It is up to Sweden and Finland to join the alliance

NATO has not ruled out any possible new members and it is up to countries such as Sweden and Finland to decide if they want to join, the head of the alliance's military committee said on Tuesday.

"It is a sovereign decision of any nation that wants to join NATO to apply for membership, which they so far have not done," Dutch Admiral Rob Bauer told reporters during a visit to Seoul. "We are forcing no one into NATO."

The alliance also had not pressured any countries to provide weapons to Ukraine, he said.

During his visit to the South Korean capital this week, Bauer discussed the Ukraine war, as well as military cooperation between Seoul and NATO.

The visit coincided with a video speech by Ukrainian President Volodymyr Zelensky to South Korea's parliament on Monday, in which he asked Seoul for any military aid it could provide, including armoured vehicles and anti-aircraft missiles.

Bauer said he discussed Zelensky's request with South Korean officials, but confirmed their stance that they would only provide non-lethal aid for now.

"If President Zelensky asks for those systems, it means he needs them," Bauer said.

However, it was up to the South Korean government if they will and can send weapons, he added, noting that NATO had not asked South Korea to provide weapons, and was not providing direct military itself, though member states are.

Bauer said the non-lethal aid, including bulletproof helmets and medical kits, that South Korea had sent was also important.

He declined to comment on reports that Russian forces may have used chemical agents in an attack on the southeastern Ukrainian city of Mariupol. NATO assessed that Russia will focus on eastern Ukraine, after having started the war on too many fronts, he said.

NATO and its members will continue to supply "everything possible" to ensure Ukraine's survival, but it would not be deploying its own aircraft or troops to the country, Bauer said.