The Senate Select Committee on Intelligence has invited Comey to testify before it, according to media reports.
Comey was earlier scheduled to testify before the committee tomorrow for a hearing on worldwide threats along with other top intelligence officials.
Acting FBI Director Andrew McCabe, however, would now take his place.
The news of the invitation to Comey comes a day after his abrupt sackingby US President Donald Trump.
His sacking triggered a political firestorm with an angry opposition calling for an appointment of a special prosecutor to investigate the alleged Russian influence in last year's general elections.
In recent days, Comey again came under fire for his handling of the investigation into Clinton's private email server. Many Democrats believe that his announcement that he was re-opening the probe 11 days before the November 8 election cost Clinton the presidency.
Comey had courted controversy during the 2016 presidential polls when he revealed a renewed investigation into Hillary Clinton's email use, which the Democrats claimed had hurt her chances of becoming president.