The head of state, a retired NATO general, said an 18-nation coalition called the Czech initiative collected the money, at a time when Europe's defence industry is falling short of the production levels needed to supply Ukraine.

Pavel told a security conference in Munich last month that the Czech Republic -- an EU and NATO member of 10.8 million people -- was able to collect a substantial amount of weaponry for Ukraine outside the continent.

He said at the time that, working with Canada and Denmark, the Czechs had "identified" 500,000 rounds of 155-millimetre ammunition and 300,000 122-millimetre shells.

"We have collected the total sum needed to buy the entire amount... as of this morning," Pavel told reporters on Thursday without disclosing the sum.

"If there are no fundamental problems, the ammunition could reach Ukraine within several weeks," he added.

The Financial Times had previously reported Prague was looking to amass $1.5 billion to pay for the munitions.

Ukrainian forces have for months been contending with a lack of ammunition as they try to hold off Russian troops, which invaded in February 2022.

Kyiv's backers have sent millions of their own shells to Ukraine, but stocks are running low.

Some of Ukraine's EU allies have also been reluctant up until now to channel defence spending to anywhere outside the bloc.

And a US aid package worth $60 billion has been held up amid wrangling in Congress.

Pavel said it was now up to the Czech government to write up a deal on the supply.

Belgium, Britain, Canada, Denmark, France, Germany, Lithuania, the Netherlands, Norway and Sweden are among countries contributing to the project.

The Netherlands has pledged to donate 100 million euros ($109 million), while Germany has offered a "three-digit million euro sum".

The EU has fallen way short of a promise made last year to deliver one million shells to Ukraine by March 2024.