British Prime Minister Keir Starmer arrived in Ukraine Thursday with a pledge to help guarantee the country’s security for a century, days before Donald Trump is sworn in as U.S. president.

The British government said Starmer and Ukrainian President Volodymyr Zelenskyy will sign a “100-Year Partnership” treaty in Kyiv covering areas including defense, science, energy and trade.

Sir Keir Starmer has vowed to put Ukraine in the "strongest possible position" this year during his first trip to Kyiv as Prime Minister. The Labour leader’s visit to the presidential palace in the capital coincided with a drone attack by Vladimir Putin ’s forces on the city.