British Foreign Secretary David Cameron promised three billion pounds ($3.74 billion) of annual military aid for Ukraine for "as long as it takes" on Thursday, adding that London had no objection to the weapons being used inside Russia.
"We will give three billion pounds every year for as long as is necessary. We've just really emptied all we can in terms of giving equipment," he told Reuters in an interview on a visit to in Kyiv, adding that the aid package was the largest from the UK so far.
"Some of that (equipment) is actually arriving in Ukraine today, while I'm here," he said.
Cameron said Ukraine had a right to use the weapons provided by London to strike targets inside Russia, and that it was up to Kyiv whether to do so.
"Ukraine has that right. Just as Russia is striking inside Ukraine, you can quite understand why Ukraine feels the need to make sure it's defending itself," Cameron told Reuters outside St. Michael's Cathedral.
Cameron, who led the UK from 2010 and 2016 as prime minister and only returned to frontline politics several months ago, met Ukraine's Foreign Minister Dmytro Kuleba and President Volodymyr Zelenskiy on his second visit to Kyiv as foreign secretary.
Britain's top diplomat celebrated the release of a long-delayed $60 billion aid package by the U.S. Congress.
"It's absolutely crucial, not just in terms of the weapons it will bring, but also the boost to morale that it will bring to people here in Ukraine."
However, Cameron did not answer directly when asked how he thought the possible re-election of Republican frontrunner Donald Trump to the White House could affect U.S. support for Ukraine.
Trump and hardline Republicans in Congress oppose further aid to Ukraine, with the possible exception of a loan.
"It's not for us to decide who the Americans choose as their president - we will work with whoever that is," Cameron said, adding that the strategy for Ukraine's allies ought to be to ensure Ukraine is on the front foot by the time of the U.S. elections in November.
