"We will be introducing comprehensive legislation in the coming days to ensure the imposition of mandatory sanctions under CAATSA while levying additional sanctions to ensure the maximum impact the Kremlin’s campaign against our democracy and the rules-based international order," the statement said adding that the bill will include sanctions on the Russian sovereign debt.
In May, the US Treasury Department prolonged sanctions already in place against a number of Russian companies until the end of October this year.
US oil and gas companies are lobbying against imposing tougher sanctions on Russia, concerned that the sanctions could jeopardize their investments in the world's greatest oil-producing country.
At the summit, the US president also expressed doubt regarding the American intelligence community's conclusion that Russia had interfered in the 2016 presidential election, an allegation that Moscow has repeatedly denied.