US immigration agents searched the home of Minnesota Representative Ilhan Omar on Monday morning as part of a “criminal investigation”.

Homeland Security Investigations (HSI) agents “executed a judicially authorized search warrant” for the home in the Washington, DC, area, a US justice department spokesperson told the BBC.

The search “is part of an ongoing federal criminal investigation,” the spokesperson said but no further details were given.

Omar was born in Somalia and came to the US aged eight fleeing war. First elected to Congress in 2018, she is running for reelection next month, and is an outspoken critic of President Donald Trump.

The US Congress is currently out of session and it is unclear if Omar was at the home. The BBC has contacted Omar for comment.

While the nature of the criminal investigation remains unclear, it is not the first time her immigration records have been scrutinised by Republicans. Earlier this year, fellow Congresswoman Nancy Mace of South Carolina unsuccessfully filed a subpoena of her records.

Last month, Homeland Security Secretary Markwayne Mullin told a conservative podcaster “something is going to happen”, alleging that Omar had previously married her brother “to try to bring him to the United States.” Her brother now lives in London, he said.

Separately, the White House border tsar Tom Homan told Fox News Omar was being investigated for unspecified immigration violations.

Omar, a Democrat, denied these allegations last month. “I will say it again so it’s as clear as possible: I’m not at all worried about these investigations, because they are complete shams,” she said in a campaign fundraising email.

She has been the target of Trump’s insults and the president previously suggested that she “should go back” to Somalia and at times said she should be deported. US citizenship is required to serve as a US House Representative.

Omar has responded to Trump’s insults and attacks describing them as “unhealthy and creepy obsession.”

The president has also spoken unfavourably about the Somali American community. Last week, he wrote on social media that Minnesota “is being taken over by Somali immigrants” and said “the people of Minnesota must fight back.”

Omar is the first Somali-American elected to the US House of Representatives and she represents a district in the Minneapolis area. She and Michigan Representative Rashida Tlaib were the first Muslim women elected to Congress.

She won the 2024 election with 74% of the vote. The timing of Monday’s raid — 22 days to the November midterm elections which will decide the balance of power for the next two years — is likely to raise concerns from Democrats.

The justice department has a longstanding policy of refraining from most enforcement action that is “likely to raise an issue or the perception” that it was being brought for the purpose of affecting any election or disadvantage a candidate.