The Justice Department's inspector general has recovered missing text messages from two FBI officials who sharply criticized Donald Trump, making them a flash point in the debate over the federal criminal investigation into Russian interference in the 2016 election.

Inspector General Michael Horowitz told lawmakers in a letter Thursday that messages sent between FBI officials Peter Strzok and Lisa Page from December 2016 to May 2017 were recovered using forensic tools after the Justice Department initially said they were among many emails on FBI-issued mobile devices that were lost due to a technical problem.

"Our efforts to recover any additional text messages is ongoing," Horowitz wrote in a letter to Senate Homeland Security and Governmental Affairs Chairman Ron Johnson and Senate Judiciary Chairman Chuck Grassley. "We will provide copies of the text messages that we recover from these devices to the department so that the department's leadership can take any management action it deems appropriate."

The department had previously notified lawmakers that about 50,000 text messages sent between Strzok and Page during that time frame had been lost. The newly recovered text messages haven't been publicly released, and Horowitz didn't specify if all 50,000 were found or only some of them.

Trump and his Republican allies in Congress have seized on text messages the two FBI officials exchanged during the 2016 presidential campaign to allege that the investigation into Russia's meddling and whether anyone associated with the president helped Moscow was started on a false pretense and has been colored by political bias.

One exchange frequently cited included remarks "that there's no way" Trump would win the election but "we can't take that risk." Special Counsel Robert Mueller removed Strzok from his team investigation Russia meddling after learning of the texts, while Page never served on Mueller's team.