Biden makes unannounced visit to Ukraine ahead of Russia invasion anniversary.

President Joe Biden made a surprise visit to Ukraine on Monday to meet with President Volodymyr Zelenskyy, in a powerful show of support just days before the one-year anniversary of Russia's invasion of the country. 

Speaking at the Mariinsky Palace, Biden emphasized the importance of Ukraine's democratic stance and assured its citizens that the world stands with them. 

Biden's visit comes at a critical time in the conflict, as both sides gear up for expected spring offensives. 

While Zelenskyy urged allies to speed up the delivery of pledged weapon systems, Biden announced an additional half-billion dollars in U.S. assistance, including shells for howitzers, anti-tank missiles, and air surveillance radars. 

However, the U.S. President stopped short of providing new advanced weaponry, which Ukraine has been pushing for. Nonetheless, Zelenskyy described the negotiations as fruitful.