The grand jury has been hearing evidence and witness testimony for several months, but had been on a recent hiatus, according to the report.
Prosecutors are investigating whether Mr Trump mishandled classified documents and later obstructed efforts to retrieve them.
The development comes after CNN revealed that the Trump legal team had been unable to locate a classified document he referred to on tape.
Attorneys for Mr Trump could not find the document he referred to when they turned over material in mid-March in response to a federal subpoena relating to the investigation, according to the report.
Mr Trump has already been indicted in New York on state charges that he paid illegal hush money payments in the lead up to the 2016 presidential election.
But should Mr Smith move forward with the indictment, it would be the first time a sitting or former US president has faced federal charges.
Mr Trump has repeatedly denied any wrongdoing.
In June 2022, FBI agents visited his private club Mar-a-Lago to retrieve documents he had taken with him when he left the White House.
Mr Trump turned over 38 classified documents, and his attorneys pledged in writing that they had completed a thorough search of the property.
The Justice Department obtained a search warrant for the former president’s home in August, and later said they retrieved 300 papers marked classified.
Mr Trump’s attorneys sought to blame the oversight on White House staff in a letter to Congress in April.
He could face charges relating to the handling of classified documents or obstructing investigators from recovering the materials.
Mr Trump has previously said that he had the power to declassify documents simply by “thinking about it”.