The British prime minister's surprise trip to Ukraine comes a day after the high-profile visit of leaders from EU countries France, Germany, Italy and Romania.
British Prime Minister Boris Johnson was in Kyiv again on Friday, a surprise visit that comes a day after four European Union leaders visited.
"I am delighted to see a great friend of our country, Boris Johnson, in Kyiv again," Ukrainian President Volodymyr Zelenskyy wrote on Telegram. "It's good to be in Kyiv again," Johnson said on his Twitter account.
Boris Johnson had already been to Kyiv on April 9, when he was the first leader of a G7 country to visit Ukraine. London has provided particularly strong military support to Kyiv since then.
According to a statement from Johnson's office, the British Prime Minister "offered to launch a major training programme for Ukrainian forces, which could train up to 10,000 troops every 120 days".
"My visit today, in the midst of war, is about sending a clear and simple message to the people of Ukraine: the UK is with you, and will be with you until victory is achieved," Johnson was quoted as saying.
"That is why I have proposed to President Zelenskyy a major military training programme, which could change the equation of this war by harnessing the most powerful force of all -- the determination of the Ukrainians to win," he added.
"Many days of war have proved that Britain's support for Ukraine is firm and resolute," Zelenskyy said. "We have a shared vision of how Ukraine can achieve victory."
Boris Johnson arrived in Kyiv a day after a groundbreaking visit by the leaders of France, Germany, Italy and Romania, all members of the European Union, unlike the UK.
They said they were in favour of granting Ukraine candidate status for EU membership, as did the European Commission on Friday -- a status Kyiv had been seeking and hopes would lead to early membership of the EU bloc.
The British prime minister is a popular figure in Ukraine due to his stance on the war -- in contrast to his standing at home where his conduct has come under intense scrutiny.
Johnson recently survived a confidence challenge from his own party, and this week saw the resignation of his second ethics adviser who quit alleging government misconduct.