Western leaders piled on military and humanitarian aid for Ukraine on Thursday while reaffirming that NATO troops will not be sent to that country as they met at an unprecedented triple summit in Brussels.

The summit was called to address the conflict in Ukraine and was attended by NATO, G7 rich nations and European leaders.

NATO announced plans for new combat units in four eastern European countries near Ukraine, while the United States and Britain increased aid and expanded sanctions to new targets, including a woman who London said was the stepdaughter of Russia's foreign minister.

The alliance also reiterated its resolve to avoid direct conflicts with Russia. 

"NATO will not deploy troops on the ground in Ukraine, because the only way to do that is to be prepared to engage in a full conflict with Russian troops," Secretary General Jens Stoltenberg said at a press conference.

The European Union was set to unveil steps to wean itself off Russian energy, something likely to drive up fuel costs even further around the continent. Moscow supplies 40 percent of the EU's collective gas needs and more than a quarter of its oil imports.

The measures stopped short of President Volodymyr Zelenskyy's call for a full boycott of Russian energy and a no-fly zone over Ukraine.

Responding to Thursday's show of unity in Brussels, Moscow said the West had itself to blame for the conflict by arming the "Kyiv regime".

Over 3.6 million people have fled Ukraine and thousands have been killed in the conflict, according to the United Nations.

(With input from Reuters)