U.S. President Donald Trump has signed legislation imposing new sanctions on Russia into law, a White House official said on Wednesday.The U.S. Congress voted last week by overwhelming margins for sanctions to punish the Russian government over interference in the 2016 presidential election, annexation of Ukraine's Crimea and other perceived violations of international norms.Trump, who has made clear he wanted to improve relations with Russia, grudgingly accepted the new congressional sanctions, which also included Iran and North Korea. The bill had enough support in Congress to override a presidential veto.Trump's signing of the bill followed some conflicting signals from the administration in recent days about the sanctions.U.S. Secretary of State Rex Tillerson told reporters on Tuesday that he and Trump did not believe the new sanctions would "be helpful to our efforts" on diplomacy with Russia. Vice President Mike Pence said that the bill showed Trump and Congress were speaking "with a unified voice."White House adviser Kellyanne Conway confirmed the signing during an interview with Fox News.Trump's desire for better relations with Moscow has been hamstrung by findings of U.S. intelligence agencies that Russia interfered to help the Republican against Democratic presidential candidate Hillary Clinton. U.S. congressional panels and a special counsel are investigating. Moscow denies any meddling and Trump denies any collusion by his campaign. The Russian rouble weakened slightly following the initial report that Trump had signed the bill.