US lawmakers Wednesday ordered two former top aides to President George W Bush to testify in an inquiry into the firings of eight federal prosecutors, which majority Democrats allege were politically motivated, according to dpa. The subpoenas against Bush's former chief legal adviser Harriet Miers and former White House director of political affairs Sara Taylor step up a confrontation between Congress and Bush over the administration's running of the Justice Department. Democrats, who won control of Congress in November elections, charge that Republican operatives at the White House, including Bush's top political strategist Karl Rove, were involved in the process of forcing out the eight US attorneys last year. Bush has offered to let top White House aides answer lawmakers' questions behind closed doors, but Democrats have pressed for public hearings in Congress. A subpoena orders a witness to testify or face legal penalties. The Senate Judiciary Committee, which is seeking Taylor's testimony, also demanded additional documents from the White House on the prosecutor firings. Miers was subpoenaed by the House of Representatives' Judiciary Committee. "Some at the White House may hope to thwart our constitutional oversight efforts by locking the doors and closing the curtains, but we will keep asking until we get to the truth," the Senate panel's chairman, Patrick Leahy, said in a prepared statement. US Attorney General Alberto Gonzales has faced blistering criticism for his handling of the affair, including evasive testimony to Congress that helped provoke calls by several Republican senators for his resignation. Bush has steadfastly backed Gonzales, an ally from Bush's days as Texas governor before he became president in 2000. A non-binding vote of no confidence in Gonzales failed last week in the Senate when Democrats failed to rally enough Republicans behind the measure. There are more than 90 US federal prosecutors, heading regional offices that conduct criminal investigations. But they have traditionally been replaced at the start of a president's term, not in the middle.