But part is because Ukraine is keeping secret the methods it hopes will help it regain a winning edge elsewhere. Participants refuse to say how they circumvented the all-seeing eyes and kill-zones of the modern battlefield.

European Union leaders will try to overcome staunch resistance to both a funding plan for Ukraine and a massive trade deal with South America during a summit in Brussels starting Thursday — insisting that the bloc’s reputation is on the line.

President Donald Trump on Monday described an end to the war in Ukraine as closer than ever, with American officials earlier in the day suggesting beefed-up security guarantees for Kyiv had advanced the peace talks — but that the US offer would not be on the table forever.

European Union leaders are set to review on Thursday proposals for using the proceeds from immobilised Russian sovereign assets, mostly held in Belgium, to support Ukraine's financial needs for the coming years - the so-called "reparations loan".

Calls are growing for the European Union to approve a massive loan to Ukraine backed by frozen Russian assets without the support of Belgium, where nearly all the assets are located.

Even under fire, Ukraine is ramping up its arms industry. President Volodymyr Zelensky says the country now produces more than 50% of the weapons it uses on the front line. Almost its entire inventory of long-range weapons is domestically made.