LONDON, Nov 9 (Reuters) - NATO Secretary General Jens Stoltenberg said on Wednesday it was "encouraging" to see Ukrainian forces being able to liberate more of the country's territory, after Russian Defence Minister Sergei Shoigu ordered his troops to withdraw from Kherson.Speaking in Downing Street, where he was meeting British Prime Minister Rishi Sunak, Stoltenberg said: "It is encouraging to see how the brave Ukrainian forces are able to liberate more Ukrainian territory.Asked later during an interview with Sky News about the Kherson retreat, he said: "It's part of an overall pattern or picture we have seen over the last month that Russia has absolutely lost the momentum.""(Stoltenberg) thanked the prime minister for the UK’s support for Ukraine, which the prime minister confirmed would continue under his leadership for as long as needed," the spokesperson said in a statement.Earlier, Stoltenberg joined British defence minister Ben Wallace to observe the training of Ukrainian troops in southeast England, as Britain announced the delivery of a further 12,000 extreme cold-weather sleeping kits for Ukraine."