The European Union will step up sanctions against Russia, foreign ministers gathered in Brussels said on Friday, but they resisted Kyiv's calls for military action that would risk dragging the NATO military alliance into the war.

In Brussels for talks with NATO and EU peers, the bloc's top diplomat Josep Borrell said that all options remained on the table with regard to new sanctions against Russia for the invasion of its neighbor Ukraine.

"We will consider everything," Borrell told reporters when asked about the possible suspension of the EU's gas imports from Russia.

Ireland's Foreign Minister Simon Coveney said a fourth round of sanctions could affect more Russian banks' access to the SWIFT international transfer system, bar Russian ships from European ports and cut imports from Russia.

"I also suspect that we'll be banning other imports like steel, timber, aluminium and possibly coal as well," he said.

It was not immediately clear, however, when the 27-nation EU would be able to agree on exact measures given member states' divisions on doing business with Moscow and some countries' heavy reliance on Russian energy supplies. "Each day the west is importing energy from Russia to the tune of $700m," Eurointelligence think-tank said in a note.

Ukrainian President Volodymyr Zelenskiy has called for Western allies to enforce a no-fly zone since Moscow's invasion started nine days ago, with Russia shelling cities and bringing fighting to Europe's largest nuclear plant.

Western powers have already punished Russia including with restrictions on central bank activities and by seizing assets from billionaire oligarchs.

NATO members have sent arms to Ukraine, but stopped short of military action that would put them in direct conflict with nuclear-armed Russia.

On Friday, U.S. Secretary of State Antony Blinken said the alliance would defend "every inch" of NATO territory from attack. Ukraine, a former Soviet republic and Moscow satellite that wants to join the European Union and the Western military club, is not a currently a member of either.

"Ours is a defensive alliance. We seek no conflict. But if conflict comes to us, we are ready for it," Blinken said. While some NATO countries indicated a willingness to discuss a no-fly zone, they made clear their reservations.

Canadian Foreign Minister Melanie Joly said that NATO must avoid triggering a wider conflict. France's presidential office described the request for a no-fly zone as "very difficult to satisfy."

NUCLEAR SCARE

Putin launched his "special military operation" to get rid of what he said was Ukraine's fascist government and demilitarize the country. Zelenskiy says Moscow is trying to prevent a liberal democracy flourishing on Russia's border.

"The truth is: It is not NATO that is threatening Putin but the desire for freedom in Ukraine. He wants to break this urge for freedom - in Ukraine, and also in his own country," German Foreign Minister Annalena Baerbock said.

In a sign of the escalating dangers of the war, a huge blaze at the site of Europe's biggest nuclear power station in Ukraine was extinguished on Friday after fighting that caused global alarm. Officials said the Zaporizhzhia plant was operating normally after it was seized by Russian forces.

Baerbock said nuclear infrastructure must stay out of the war. She added the 27-nation EU would give Ukraine humanitarian aid and shelter its refugees, as well as moving ahead with more sanctions against Russia.

On Thursday, Zelenskiy said that if allies wouldn't meet his request to protect Ukrainian air space, they should instead provide Kyiv with more war planes.

"We have 15 nuclear units so these units, two in the east are close to the front line of war. It's not just a Ukrainian question," Energy Minister Herman Halushchenko told Reuters. "We are fighting. We will fight to the end."