MOSCOW (Reuters) - Russian Prime Minister Vladimir Putin praised the New START nuclear arms treaty with the United States on Wednesday in his first remarks on the pact since the US Senate approved it last week. Putin lauded President Dmitry Medvedev for forging the treaty with President Barack Obama - a clear signal of approval for the agreement from Russias paramount leader, who also stands to benefit from the improvement in bilateral ties. Analysts say Russia would not have agreed the treaty without Putins support and that the Kremlin-controlled parliament is all but certain to ratify it after the holidays. It is the main product of Obamas effort to reset long-strained ties between Washington and Moscow, a drive that Medvedev has embraced enthusiastically. Putin has rarely commented on the New START treaty and at one point during year-long negotiations made remarks that cast doubt on the chances for agreement. On Wednesday, Putin suggested the treaty would bolster international security but also help Russia develop its economy by improving the investment climate. I would like to congratulate Dmitry Anatolyevich (Medvedev) on the completion of work on the START treaty, Putin said at a govt meeting attended by the president. This is a serious decision which will have an impact not only on issues related to international security, Putin said. For us it is important because it creates favourable external conditions for realization of social and economic initiatives inside this country. Signed by Medvedev and Obama in April, the pact commits the United States and Russia to reducing their arsenals of deployed strategic nuclear weapons and establishes monitoring rules officials say will improve trust between the Cold War foes. Putin steered Medvedev into the presidency as his chosen successor in 2008 and has hinted he will either return to the Kremlin or leave his protege in place in the 2012 election. Analysts say Medvedev was given a mandate to improve relations with the West, which deteriorated during Putins presidency and hit a low with Moscows August 2008 war with pro-Western Georgia, in hopes of strengthening Russias economy. At the meeting on Wednesday, Medvedev lamented a lack of progress in attracting investment, saying there is very little improvement in the investment climate. We need to work on it. Putin gave a cautious assessment of Russias campaign for membership of the World Trade Organization, which has gotten a boost from Obamas public backing as part of the reset. Many questions remain but there is some movement forward. There is no final result yet but we have agreed the main parameter with our main partners, Putin said. The European Union gave its formal backing to Russian membership of the WTO this month, and officials say Russia could join the trade-rules body next year.