The agreement is intended “to be the first step in developing an unshakeable hundred-year partnership between Ukraine and the United Kingdom,” the statement said. London would also “provide intelligence sharing, cyber security, medical and military training, and defense industrial cooperation.”

Britain is already one of Ukraine’s strongest supporters but Sunak’s visit and the additional help delivered a particularly uplifting message for Kyiv at a moment when Russia has stepped up its aerial bombardment campaign and when other, larger, proposed aid packages from the United States and the European Union are stalled in Washington and Brussels.

Although the British assistance is relatively small compared with more than $60 billion sought by President Biden and, so far, blocked in Congress, Sunak’s announcement showed his country’s support was unwavering in the face of Russia’s continued aggression against Ukraine and its unchecked disregard for internationally recognized borders.

Kyiv has sought security commitments from Western governments that could deter Russia and send a signal to Moscow that support for Ukraine remains strong.

The Group of Seven countries agreed to a framework of security guarantees at the NATO summit in Vilnius, Lithuania, in July, with individual states intended to negotiate and sign bilateral agreements separately. “The U.K. is the first country to deliver a final agreement,” the government statement said.

Sunak also arrived in Kyiv with a pledge to provide some $250 million more in military aid than the previous two years.

Much of this sum would be spent “on a major push to rapidly procure and produce thousands of military drones for Ukraine, including surveillance, long-range strike and sea drones,” the statement said.

“This will be the largest delivery of drones to Ukraine from any nation,” the statement said. “Most of the drones are expected to be manufactured in the UK.”

Sunak’s visit takes place as questions have arisen over the West’s commitment to helping Ukraine defend itself. Some Republicans in Congress have blocked Biden’s proposal and sought to link it provisions for U.S. border security.

On Thursday, National Security Council spokesman John Kirby said that assistance to Ukraine has “ground to a halt,” as the last aid package under existing financial support had been disbursed.

In Brussels, Hungarian Prime Minister Viktor Orban has thrown up obstacles to new European Union assistance.

Sunak, by contrast, arrived in Kyiv on Friday with a message of steadfast support.

“I am here today with one message: the UK will also not falter. We will stand with Ukraine, in their darkest hours and in the better times to come,” Sunak said, according to the government statement.