EU leaders grappled at a summit meeting Thursday with how to get more weapons to Ukraine's outgunned forces while also re-arming their own countries in the face of Russia's emboldened President Vladimir Putin.

Over two years into Moscow's war against its neighbour, Kyiv's troops are struggling to hold back the Russian army as Western deliveries of ammunition have faltered.

Putin meanwhile has tightened his iron grip over his country by winning a new six-year term at elections after opposition was crushed.

"On Ukraine, we need to continue and certainly accelerate our support," Belgium Prime Minister Alexander De Croo said at the start of the meeting.

"The necessity today is ammunition."

As a $60 billion package remains stalled in Washington, the European Union's 27 leaders debated a plan to spend profits from 200 billion euros in frozen Russian central bank assets on weapons for Ukraine.

The proposal could unlock some three billion euros ($3.3 billion) a year for Kyiv, but leaders were not expected to give the final go-ahead on Thursday.

That would come on top of more than 33 billion euros that the EU says it has provided towards arming Ukraine since the Kremlin invaded in February 2022.

Germany's Chancellor Olaf Scholz, who had been cautious about undermining EU markets, threw his weight behind the plan as legally sound.

But the Kremlin warned it would use legal and "other methods of retaliation" to hit back.

Alongside the efforts to get more weapons to Kyiv, the EU is also scrambling for ways to boost Europe's defence industry to be able to arm Ukraine and build up its own forces.

Brussels has put forward a raft of proposals aimed at ramping up capacity but there are complaints that Europe is still not moving fast enough.

While Russia has put its economy on a war footing, the EU has fallen well short of a promise made last year to supply Ukraine with a million artillery shells by this month.

Meanwhile, the Czech Republic has spearheaded its own initiative aimed at hoovering up hundreds of thousands of shells available around the world to send to Kyiv.

Defence bonds?

France and Estonia have pitched the idea of using joint borrowing, similar to the massive package of support the EU came up with during the Covid pandemic, to fund defence spending.

But a majority of member states, led by so-called "frugal" countries such as Germany, are unwilling to go anywhere near that far.

"If that doesn't fly, then propose something else, some other solution that we can solve this problem, because there is a big problem of funding the defence industry," Estonian Prime Minister Kaja Kallas said.

Instead, the discussion was set to focus on getting the EU's lending arm, the European Investment Bank, to expand its funding for the sector.

At the moment, the bank is limited to investing in only a small number of "dual-use products" that can have both military and civilian functions.

While the response to the conflict in Ukraine was set to dominate the summit, EU leaders were also looking for a united stance on the war in Gaza, with United Nations chief Antonio Guterres in attendance.

Diplomats say an overwhelming majority of countries support a call for an "immediate humanitarian pause" in Israel's offensive and a warning for it not to launch a ground operation in Rafah.

But Irish premier Leo Varadkar said staunch Israeli allies the Czech Republic and Austria were reluctant to back that wording, in the latest obstacle to EU unity on the issue.

"The response to the appalling crisis in Palestine has not been Europe's finest hour, quite frankly," he said.

Closer to home, EU leaders look set to give the green light to opening membership negotiations with Bosnia as Russia's war has sparked a push to expand the bloc.

Diplomats said that the Balkan state would likely get an agreement on launching talks, but they could only start in earnest when the country has passed more reforms.

"It's a two-step approach," Dutch Prime Minister Mark Rutte said.

"Yes, opening membership talks, but also, yes, working on all the outstanding issues before we can take the next step