President Trump's personal lawyer, Michael Cohen, is now one of the people included in the widening congressional probe into Russia's meddling in the 2016 election.

Cohen told ABC News in an email House and Senate investigators asked him to "provide information and testimony" about any interactions he had with people tied to the Russian government, but Cohen declined their request.

"I declined the invitation to participate as the request was poorly phrased, overly broad and not capable of being answered," Cohen said in an email Tuesday.

Congressional investigators have already asked four people who worked closely with the Trump campaign for records related to contacts they've had with Russian officials.

Former national security adviser Mike Flynn, who was subpoenaed, cited his Fifth Amendment rights and declined to hand over any records.

Former Trump campaign manager Paul Manafort, Trump's informal adviser Roger Stone and former foreign policy adviser Carter Page are all producing records for congressional investigators.

After Cohen declined to provide congressional investigators with information, the Senate Select Intelligence Committee voted unanimously to grant Chairman Richard Burr, R-N.C., and Vice Chairman Mark Warner, D-Va., the power to issue subpoenas.

Cohen is a notoriously feisty defender of Trump and is now a top fundraiser for the Republican National Committee.

The American intelligence community believes Russia interfered in the 2016 presidential election, namely by hacking the emails of the Democratic National Committee and Hillary Clinton campaign aides. The Kremlin has denied any involvement, but intelligence officers believe the Russians developed a preference for Trump over Clinton during their activities.

No evidence has been produced tying Trump's campaign to the Russian government.

However, Manafort, Flynn and Page all had close ties to the Russian government from work that started before they came to work on Trump's campaign. Critics allege they could have been possible links between Trump's campaign and the Kremlin, but they have denied those allegations.