KYIV, Ukraine (AP) — President Joe Biden swept unannounced into Ukraine on Monday to meet with President Volodymyr Zelenskyy, in a defiant display of Western solidarity with a country still fighting what he called “a brutal and unjust war”, days before the first anniversary of Russia’s invasion.

“One year later, Kyiv stands,” Biden declared after meeting Zelenskyy at Mariinsky Palace. Jabbing his finger for emphasis on his podium, against a backdrop of three flags from each country, he continued: “And Ukraine stands. Democracy stands. The Americans stand with you, and the world stands with you.”

Biden spent more than five hours in the Ukrainian capital, consulting with Zelenskyy on next steps, honouring the country’s fallen soldiers, and seeing US embassy staff in the besieged country.

The visit comes at a crucial moment: Biden is trying to keep allies unified in their support for Ukraine as the war is expected to intensify with spring offensives. Zelenskyy is pressing allies to speed up delivery of promised weapon systems and is calling on the West to provide fighter jets — something that Biden has declined to do.

The US president got a taste of the terror that Ukrainians have lived with for close to a year when air raid sirens howled just as he and Zelenskyy wrapped up a visit to the gold-domed St Michael’s Cathedral.

Looking solemn, they continued unperturbed as they laid two wreaths and held a moment of silence at the Wall of Remembrance honouring Ukrainian soldiers killed since 2014, the year Russia annexed Ukraine’s Crimean Peninsula and Russian-backed fighting erupted in eastern Ukraine.

The White House would not go into specifics but National Security Advisor Jake Sullivan said that it notified Moscow of Biden’s visit to Kyiv shortly before his departure from Washington, “for deconfliction purposes” in an effort to avoid any miscalculation that could bring the two nuclear-armed nations into direct conflict.

In Kyiv, Biden announced an additional half-billion dollars in US assistance — on top of the more than US$50 billion already provided — for shells for howitzers, anti-tank missiles, air surveillance radars and other aid, but no new, advanced weaponry.

Ukraine has also been pushing for battlefield systems that would allow its forces to strike Russian targets that have been moved back from front line areas, out of the range of HIMARS missiles that have already been delivered. Zelenskyy said he and Biden spoke about “long-range weapons and the weapons that may still be supplied to Ukraine even though it wasn’t supplied before”. But he did not detail any new commitments.