<b>Live updates: follow the latest news on </b><a href="https://www.thenationalnews.com/world/2022/02/18/russia-ukraine-latest-news/"><b>Russia-Ukraine</b></a> A senior US defence official said on Monday that Russia’s offensive in Ukraine, now in its third week, remains stalled across different cities but there is no sign of the Kremlin backing down. “Almost all of Russia's advances remain stalled,” the official said, with the Russian military facing mounting challenges on the battlefront. But despite those challenges, the Pentagon saw no sign of Russia slowing its battlefield tempo. “We<a href="https://www.thenationalnews.com/world/2022/02/18/russia-ukraine-latest-news/" target="_blank"> want to see a ceasefire</a> … but what we are seeing is still a very concerted Russian efforts to continue with ever more violence.” The official estimated that Russian forces continue to be stalled about 15 kilometres from Kyiv’s city centre while the <a href="https://www.thenationalnews.com/world/2022/03/12/fighting-rages-across-ukraine-as-mosque-is-shelled-in-mariupol/" target="_blank">bombardments of Mariupol</a> and Kharkiv continue, though Moscow has been unable to prevail on either front. The Pentagon added that Russia has now fired more than 900 missiles in Ukraine but has yet to achieve air superiority. “The Russians, for all their inventory and for all the munitions that they have available to them … they have still not achieved air superiority over all of Ukraine,” the official said. Asked about the Russian strike on the Yavoriv military base close to the Polish border on Sunday, the US official said it involved “several dozen” missiles fired from bombers flying inside Russian airspace. But he added that the strike, which <a href="https://www.thenationalnews.com/world/uk-news/2022/03/14/ex-nato-deputy-chief-says-russian-attack-near-poland-should-serve-as-wake-up-call/" target="_blank">occurred alarmingly close to a Nato country,</a> will not affect the US military posture in Poland or assistance flowing to Ukraine. “I would just tell you that the that the strike on Yavoriv has not changed our posture and it certainly hasn't precipitated any specific decision to move or reposition anybody else [out] of Poland.” He added that part of the $350 million security package authorised by President Joe Biden for Ukraine last month will soon be delivered. “We are fast at work on filling that out,” he said. Russia warned the West on Saturday against sending further weapons to Kyiv, saying that convoys carrying weaponry to Ukraine could be considered “legitimate targets”. The official also noted that Ukraine is using drones sent by Turkey “effectively” and that it still has “a significant majority of their inventory left". Ukraine has received Turkish-made Bayraktar TB2 drones that have been reportedly used to attack Russian tanks and missile launchers over the past three weeks. The US official said Washington is holding talks with allies and partners on boosting Ukraine’s weapons capabilities. Mr Biden spoke with <a href="https://www.thenationalnews.com/opinion/comment/2022/03/14/europes-refugee-burden-is-looming-and-poland-has-set-an-example/" target="_blank">Turkish President Recep Tayyip Erdogan</a> on Thursday and the two leaders “reaffirmed their strong support for the government and people of Ukraine”, the White House said.