WASHINGTON - President Joe Biden called for funding to investigate complaints of white supremacist beliefs at US immigration enforcement agencies in his first budget request to Congress on Friday, but officials offered no explanation for what prompted his request.The Biden administration is asking Congress to increase the funding level for workforce oversight offices within US Customs and Border Protection (CBP) and US Immigration and Customs Enforcement (ICE) to $470 million, a 22% increase over the current level, for the fiscal year that begins in October.The additional funding would ensure that workforce complaints - "including those related to white supremacy or ideological and non-ideological beliefs" - are investigated quickly, according to a summary of Biden's budget proposal. It was unclear whether any specific incidents sparked the call for the increased funding. The US Department of Homeland Security (DHS) and the White House did not immediately respond to requests for comment.Representatives at the border patrol and ICE unions did not immediately respond to requests for comment.The Biden administration has made battling domestic extremism a priority. An October 2020 DHS report said domestic violent extremists, including white supremacists, pose "the most persistent and lethal threat" to the United States.Border patrol agents faced scrutiny in 2019 when media outlets exposed racist and misogynistic comments posted to a private Facebook group for current and former agents. Posts included jokes about the deaths of migrants and sexually explicit comments referring to US Representative Alexandria Ocasio-Cortez, a Democrat like Biden. The budget summary released on Friday did not make a similar funding request for the US military, which has also faced concerns over white nationalism and other extremism in its ranks. Defense Secretary Lloyd Austin is under pressure to show progress fighting extremism after current and former military service members were found to have participated in a Jan. 6 attack on the US Capitol.John Sandweg, an acting ICE director under former President Barack Obama, said while complaints should be investigated, Biden's decision to single out CBP and ICE employees risks sparking opposition from agents and officers."This type of language could create some concerns in the workforce that there will be political ideological tests," Sandweg said, adding that the specific language may change when the budget is enacted.Broadly increasing funding for the internal offices that probe workplace complaints is a good idea though, Sandweg said.'ROOTING OUT THE BAD APPLES'Roy Villareal, a former chief patrol agent with the US Border Patrol in Arizona, said he was "disgusted" by Biden's decision to single out his former agency.Villareal, who retired in December, said he supports "rooting out the bad apples" but said there was not widespread white supremacy and racism at CBP.Hispanics made up more than half of the Border Patrol workforce in 2016, according to DHS data. Some advocacy groups have called for greater oversight of US immigration enforcement agencies, however.In a February report, the Washington-based American Immigration Council said the Border Patrol has been "steeped in institutional racism" since its creation in 1924. The report detailed past instances of agents using racial slurs, sexual comments and other offensive language.The White House budget proposal is a request of Congress to provide funding in fiscal year 2022, which begins on Oct. 1, 2021. The document reflects Biden's position on the spending, which will ultimately need to be appropriated by Congress.