Donald Trump has suggested his controversial ally Bill Pulte will investigate “rigged elections” while serving as the country’s top intelligence official, as the US president continues to make unfounded allegations about voting.

But Pulte, whom Trump appointed as acting director of national intelligence earlier this week, will only serve in the role temporarily, the president claimed on Thursday.

Speaking to reporters, Trump said: “He’s not going to be permanent because, you know, I don’t think he’d want to be permanent.”

Trump went on to say that Pulte’s “energy” and “high integrity” will “be very good”, adding: “Again, it’s short term, but he may be very effective for a short period.”

Pulte, who is currently the director of the Federal Housing Finance Agency, is a staunch Trump loyalist and does not have national intelligence experience. His appointment as head of national intelligence followed the exit of Tulsi Gabbard.

“He’s a very smart guy,” Trump claimed on Thursday, “and you may find out some things about the rigged elections, etc, etc.”

Earlier in the day, in a social media post at 12.48am, the president alleged without evidence that Democrats were cheating in California’s primaries. He also claimed the US attorney’s office in Los Angeles was investigating. The US attorney’s office said it had no comment.

Pulte’s selection for the acting intelligence role has sparked bipartisan criticism in recent days, with John Thune, the Senate’s Republican majority leader, saying that “we don’t need a weaponized” national intelligence director, adding that Pulte would have a “lengthy road ahead of him” if nominated for the role permanently. “We need professionals here,” Thune added.

Meanwhile, the Republican senator Mitch McConnell indirectly expressed his disapproval with Pulte’s nomination, saying: “Anyone performing this role of such immense public trust must have the extensive national security experience required by statute, and no nominee who falls short of this requirement will earn my vote.”

Senator Mark Warner of Virginia, the top Democrat on the intelligence committee, said: “Rather than selecting a respected national security professional capable of delivering independent judgments, the president has chosen an official who has demonstrated not just willingness but eagerness to use the authorities of government to pursue political retribution.”

Pulte burst into the national spotlight last year when he referred the Federal Reserve governor Lisa Cook; the New York attorney general, Letitia James; the former California representative Eric Swalwell; and the California senator Adam Schiff for mortgage fraud. The allegations were viewed as weak and, critics alleged, politically motivated.