RAMSTEIN AIR BASE, Germany - United States President Joe Biden approved an additional US$675 million (S$948.90 million) weapons package for Ukraine, Defence Secretary Lloyd Austin said on Thursday, as ministers met to discuss how to give Kyiv long-term support in countering Russia's invasion.

The six-month-old conflict has killed thousands and reduced Ukrainian cities to rubble.

In recent weeks, fears have grown over a potential disaster at Zaporizhzhia, Europe's biggest nuclear power plant.

Mr Austin, who was speaking at the start of a meeting of dozens of defence ministers at Ramstein air base in Germany, said the gathering would discuss how countries can work together to train Ukrainian forces and improve their defences.

"This contact group needs to position itself to sustain Ukraine's brave defenders for the long haul," Mr Austin said, referring to the meeting.

"That means a continued and determined flow of capability now."

The conflict has settled into a war of attrition fought primarily in eastern and southern Ukraine.

The latest US package will include more ammunitions, humvees and anti-tank systems.

Washington has already provided more than US$10 billion in military assistance to President Volodymyr Zelensky's government since Russian troops invaded on Feb 24.

Russian President Vladimir Putin calls the campaign a "special operation" to demilitarise Ukraine, while Kyiv accuses Moscow of an imperial-style land-grab to retake a pro-Western neighbour that shook off Russian domination when the Soviet Union broke up in 1991.