WASHINGTON - U.S. President Donald Trump said Sunday that he twice "strongly pressed" Russian President Vladimir Putin about Russia's meddling in last year's U.S. election and it was now time to "move forward in working constructively" with Moscow.

I strongly pressed President Putin twice about Russian meddling in our election. He vehemently denied it. I%27ve already given my opinion.....

Trump Says He Twice 'Strongly Pressed' Putin on US Election Meddling

In a string of Twitter comments after returning to Washington from the G-20 summit in Hamburg, Germany, Trump noted that Putin vehemently denied any role in interfering in the election and that he and the Russian leader "discussed forming an impenetrable Cyber Security unit so that election hacking, & many other negative things, will be guarded and safe."

Trump Says He Twice 'Strongly Pressed' Putin on US Election Meddling

Putin & I discussed forming an impenetrable Cyber Security unit so that election hacking, & many other negative things, will be guarded..

Trump Says He Twice 'Strongly Pressed' Putin on US Election Meddling

Key Republican lawmakers, however, immediately ridiculed Trump's idea of working with the Russians on a cybersecurity pact. Senator Lindsey Graham said on NBC's "Meet the Press" that it was "not the dumbest idea I've ever heard, but it's pretty close."

By the end of the day on Sunday Trump had backtracked on his push for the cybersecurity unit, tweeting that he did not think it could happen.

"The fact that President Putin and I discussed a Cyber Security unit doesn't mean I think it can happen. It can't," Trump said on Twitter. He then noted that an agreement with Russia for a ceasefire in Syria "can & did" happen.

U.S. Secretary of State Rex Tillerson said in Kyiv that Russian interference in the November election remains an impediment to better relations between the two countries. White House chief of staff Reince Priebus told Fox News that Trump "absolutely did not believe" Putin's denial of the election meddling.

Trump said in one tweet that he had "already given my opinion" on the election interference. He apparently was referring to the assessment he offered last week at a news conference in Warsaw, where he said, "I think it was Russia and I think it could have been other people and other countries. Could have been a lot of people [who] interfered."

Trump is facing months of investigations of allegations that his campaign colluded with Russian officials to help him win the White House and that he possibly obstructed justice by firing James Comey, then the director of the Federal Bureau of Investigation, while he was leading the agency's Russia investigation.

Numerous congressional probes are underway, as is a criminal investigation headed by Special Counsel Robert Mueller, another former FBI chief.

Trump called the summit of the leaders of the world's largest economies "a great success for the U.S.," saying he had "explained that the U.S. must fix the many bad trade deals it has made" and that its deals would be reworked.

The G 20 Summit was a great success for the U.S. - Explained that the U.S. must fix the many bad trade deals it has made. Will get done!

He made no mention of the European Union's major trade deal with Japan announced last week, or that the other 19 countries at the summit voiced their opposition to Trump's withdrawal from the 2015 international accord reached in Paris to curb greenhouse gas emissions in the coming years.

Trump claimed as a success his agreement with Putin on a negotiated cease-fire in parts of Syria that he said would save lives in Syria's unending six-year civil war for control of the Middle Eastern country.

But in his tweets, the U.S. leader also returned to two of his favorite themes, attacking the mainstream U.S. news media and opposition Democrats.

He said "Fake News" had overstated the number of American intelligence agencies that had concluded that Russia meddled in the election to boost Trump's chances of defeating Democrat Hillary Clinton, a former U.S. secretary of state, saying it was 17 when it was actually four.

Trump, as he did overseas, questioned why his predecessor, former President Barack Obama, did "NOTHING when he had info" about the Russian election interference in August, three months before the election.

Weeks after the voting, Obama, in response to Moscow's election interference, expelled 35 Russian diplomats and closed two Russian compounds that the U.S. said had been used for intelligence gathering.

Trump said he and Putin did not discuss the sanctions and that "nothing will be done" about them until "problems" with Russia's military involvement in Ukraine and Syria "are solved."

Sanctions were not discussed at my meeting with President Putin. Nothing will be done until the Ukrainian & Syrian problems are solved!