WASHINGTON -- A day after he grudgingly signed into law new sanctions against Russia, President Trump on Thursday blamed Congress for declining relations with the country that is accused of meddling in last year's presidential election.

"Our relationship with Russia is at an all-time & very dangerous low," Trump tweeted. "You can thank Congress, the same people that can't even give us HCare!"

Both houses of Congress overwhelmingly passed a new package of sanctions against Russia, Iran and North Korea – but included a key provision preventing Trump from easing or waiving the penalties on Russia unless lawmakers approve.

When signing the sanctions into law on Thursday, Trump said the bill encroached on the president's authority to negotiate deals with leaders of other countries.

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Lawmakers from both parties brushed off Trump's criticism, while Russia attacked the president on his most popular social media platform, Twitter.

"The Trump administration has shown its total weakness by handing over executive power to Congress in the most humiliating way," tweeted Russian Prime Minister Dmitry Medvedev.

Sen. Tom Cotton, R-Ark., a supporter of both Trump and the sanctions bill, said responsibility for poor U.S.-Russia relations rests with President Vladimir Putin. He cited Russia's attempts to interfere in last year's election through a campaign of cyberattacks and fake news as well as its threats to neighboring countries.

"It's Vladimir Putin's fault," Cotton said on MSNBC's Morning Joe.

Trump continues to equivocate on whether he believes the U.S. assessment that Putin directed the interference in the presidential elections, and Congress passed the sanctions bill at a time when special counsel Robert Mueller and multiple congressional committees are investigating Russia's hacking of Democrats and whether the government colluded with Trump's campaign.

The bill was intended to allay concerns among lawmakers that the president’s push for better relations with Putin might lead him to relax the penalties without first securing concessions from the Kremlin.

"We want to make sure the president will not lift these sanctions," said Sen. Dick Durbin, D-Ill., on MSNBC.