British Prime Minister Keir Starmer arrived in the Ukrainian capital of Kyiv on Thursday morning.

During the visit, Starmer and Ukrainian President Volodymyr Zelenskyy signed a "100-Year Partnership" treaty that covers the areas of security, science, energy and trade. It aims to strengthen military cooperation to enhance security in the Baltic, Black and Azov Seas and deter Russian aggression.

"Together we signed a landmark agreement, the very first of its kind, a new partnership between the UK and Ukraine that reflects the huge affection that exists between our two nations," Starmer told reporters.

"Today is a truly historic day, our relationship is closer than ever," Zelenskyy told media after the signing.

What else did Starmer say?

In a joint press conference with Zelenskyy, Starmer also said his country would play its full part in ensuring Ukraine's security and that talks on the issue would continue for months.

According to Starmer, his government would supply Ukraine with a new mobile air defense system that would be would be "developed to meet Ukraine's needs."

"[Russian President Vladimir] Putin's ambition to wrench Ukraine away from its closest partners has been a monumental strategic failure. Instead, we are closer than ever, and this partnership will take that friendship to the next level," Starmer said ahead of the visit.

Uncertainty before Trump's return

It is Starmer's first trip to Ukraine as prime minister since taking office in the summer. However, he also visited the country in 2023, when he was opposition leader, and held talks with Zelenskyy in London twice as prime minister.

The unannounced visit is the latest show of support for Ukraine from European leaders ahead of US President-elect Donald Trump's return to power in the United States.

Italian Defense Minister Guido Crosetto is also visiting Kyiv on Thursday. And German Defense Minister Boris Pistorius visited the country this week.

Trump's return to the White House has raised concerns that Ukraine could have to agree to a truce which could see it cede large parts of the country to Russia.

UK is one of Ukraine's main supporters

During the visit, Starmer is also expected to announce a further 40 million pounds (€47.5 million or $49 million) for Ukraine's post-war economic recovery.

Zelenskyy had earlier said that he and Starmer would discuss the possibility of Western troops being stationed in Ukraine to monitor a ceasefire agreement, a proposal originally put forward by French President Emmanuel Macron.

The UK is one of Ukraine's biggest military backers. It has pledged 12.8 billion pounds in military and civilian aid since Russia's full-scale invasion nearly three years ago. It has also trained more than 50,000 Ukrainian troops on British soil.

dh/rmt (AP, AFP, dpa, Reuters)