President Volodymyr Zelenskiy said it would remain until Ukraine joined NATO, describing it as an "unprecedented security agreement."

The agreement set out the support that London would continue to provide, including intelligence sharing, medical and military training, and defense industrial cooperation.

On his trip to Kyiv, British Prime Minister Rishi Sunak also increased Britain's financial support to 2.5 billion pounds - an increase of 200 million on the two previous years.

SUNAK: "This will include more air defense equipment, more anti-tank weapons, more long range missiles, thousands of round of ammunition and artillery shells, training for thousands more Ukrainian servicemen and women. And 200 million pounds to build thousands more drones - the single largest package of drones given to Ukraine by any nation."

With the Russian invasion of Ukraine approaching two years old, the visit comes at an important juncture.

Political infighting in the U.S. and European Union has held up two major packages of assistance which Ukraine heavily relies on.

SUNAK: "Our opponents around the world believe that we have neither the patience nor resources for long wars. So waver now, and we embolden not just Putin, but his allies in North Korea, Iran and elsewhere. That's why the United Kingdom and the free world will continue to stand with Ukraine as we have since the very beginning of this war."

Ukraine's ground forces commander Oleksandr Syrskiy told Reuters on Friday, Kyiv needed more military aircraft for its war effort, such as U.S. attack jets to support infantry and planes that could fire long-range cruise missiles.

SYRSKIY: "There are active debates going on about what type of aircraft we need. I can tell you we need modern aircraft that are capable of carrying and using the most modern weaponry. First of all long range, guided missiles. That's first. Secondly, for me as a commander of (ground) forces, it is important to have aviation that would support infantry, ground troops, that is combat aircraft."

Zelenskiy told the press conference he felt vital U.S. financial assistance would materialize and that he felt more positive now than last month.