Washington, Sep 18 (IANS): US President Donald Trump's personal attorney Michael Cohen is expected to appear on Tuesday before the Senate Intelligence Committee which is probing alleged Russian collusion in the 2016 election, the media reported.

It is expected that the committee staff will interview Cohen but he is not expected to be under oath during the appearance, informed sources told CNN on Sunday.

Cohen's appearance before the committee is also voluntary.

In May, Cohen had said that he was declining invitations to testify before the House and Senate intelligence committees, which are pursuing investigations into Russia's alleged efforts to influence last year's election and any potential collusion by the Trump campaign.

But he said at the time that he would "gladly" comply with a subpoena compelling his testimony and that he had nothing to hide.

Cohen is a longtime associate of the President, playing a prominent role in his business empire and supporting his presidential campaign.

Cohen's expected appearance Tuesday would follow congressional efforts to speak with or take testimony from other key figures in Trump's presidential bid.

Earlier this month, Trump's eldest son, Donald Trump Jr., spoke at length with Senate judiciary committee staff, and the panel's top Democrat, Senator Dianne Feinstein on Sunday told CNN that the committee's leadership plans to call him in for public testimony.

Feinstein said that her panel would subpoena former Trump campaign chairman Paul Manafort should he refuse a request to appear before the committee.