President Donald Trump, his three oldest children and the Trump Organization have sued Deutsche Bank AG and Capital One Financial Corp to try to block them from responding to U.S. congressional subpoenas issued by Democrats seeking financial records.

The lawsuit filed late Monday opens a new front in Trump's battle to stop the Democratic-led House of Representatives from probing the Republican president, his family, his businesses and his administration after special counsel Robert Mueller finished his inquiry into Russia's role in the 2016 election.

The lawsuit said urgent action was necessary because both banks signaled they would begin responding to the subpoenas unless a court intervened by May 6.