A look at where the investigations related to U.S. President Donald Trump stand and what may lie ahead for him:

WHAT'S THIS ALL ABOUT?

Trump is facing criminal investigations in Washington and New York.

Special counsel Robert Mueller is looking into whether the Trump campaign co-ordinated with Russia and whether the president obstructed the investigation. Trump also plays a central role in a separate case in New York, where prosecutors have implicated him in a crime. They say Trump directed his personal lawyer Michael Cohen to make illegal hush-money payments to two women as a way to quash potential sex scandals during the campaign.

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WHAT DO I NEED TO KNOW TODAY?

A published report said federal law enforcement officials were so concerned about Trump's behaviour in the days after he fired James Comey as FBI director that they opened an investigation into whether Trump had been working for Russia against U.S. interests. The New York Times cited unnamed former law enforcement officials and others familiar with the investigation.

Trump reacted with outrage during a telephone interview broadcast on Fox News Channel after host Jeanine Pirro asked whether he currently or has ever worked for Russia.

"I think it's the most insulting thing I've ever been asked," he said. "I think it's the most insulting article I've ever had written, and if you read the article you'll see that they found absolutely nothing."

Trump went on to say that no president has taken a harder stance against Russia than he has.

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FORMER TRUMP LAWYER TO TESTIFY BEFORE CONGRESS

Cohen will testify publicly before a House committee next month. The House hearing could serve as the opening salvo in a promised Democratic effort to greater scrutinize Trump, his conflicts of interest and his ties to Russia.

The House Oversight and Reform Committee announced Thursday that Cohen will testify before that panel Feb. 7, a little more than a month after the Democrats took the House majority.

The hearing marks the latest step in Cohen's transformation from a trusted legal adviser to the president to a public antagonist who has co-operated extensively against him. It is likely to pull back the curtain on key episodes involving Trump's personal life and business dealings, including hush-money payments to women and a proposed Moscow real estate deal, that federal prosecutors have been dissecting for months.

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SO ... DID THE TRUMP CAMPAIGN COLLUDE WITH RUSSIA?

There is no smoking gun when it comes to the question of Russia collusion. But the evidence so far shows a broad range of Trump associates had Russia-related contacts during the 2016 presidential campaign and transition period, and several lied about the communication.

There is also evidence that some people in the president's orbit were discussing a possible email dump from WikiLeaks before it occurred. American intelligence agencies and Mueller have said Russia was the source of hacked material released by WikiLeaks during the campaign that was damaging to Hillary Clinton's presidential effort.

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OTHER QUESTIONS TO CONSIDER:

--WHAT ABOUT OBSTRUCTION OF JUSTICE? That is another unresolved question that Mueller is pursuing. Investigators have examined key episodes such as Trump's firing of former FBI Director James Comey and his fury over the recusal from the investigation of former Attorney General Jeff Sessions.

--WHAT DOES TRUMP HAVE TO SAY ABOUT ALL THIS? Trump has repeatedly slammed the Mueller investigation as a "witch hunt" and insisted there was "NO COLLUSION" with Russia. He also says his now-former lawyer, Cohen, lied to get a lighter sentence in New York.