The US Democratic Party has forced the Senate to hold a rare closed session to debate intelligence used to justify the 2003 invasion of Iraq.
Democrats dispute the intelligence used to justify the Iraq war
The Democrats said they had acted because Republicans were refusing to hold a full investigation into the government's use of intelligence.
Republicans said it was a political stunt by the Democrats, but both sides have now agreed to finish the inquiry.
Republican leader Bill Frist accused the Democrats of hijacking the Senate.
In a speech on the Senate floor, Democratic leader Harry Reid demanded the Senate go into closed session.
The public was ordered out of the chamber, the lights were dimmed, television cameras were turned off and the doors were closed.
No vote is required in such circumstances. Previous secret sessions to discuss classified material have always been held by the agreement of the two parties.
It was last used in 1999 to debate then President Bill Clinton's impeachment trial.
Under Senate rules, the private session could be halted by a majority vote but it took the Republicans two hours to find the necessary numbers.
By that time, the BBC's Justin Webb reports from Washington, prominent coverage in Wednesday's papers had been assured.
The secret debate is being seen as a big coup for the Democrats - who are in a minority in both Houses of Congress - and a sign of their new-found confidence after the indictment last week of Vice-President Dick Cheney's chief of staff, Lewis Libby.
It was a piece of political theatre staged by a party which for years has been disunited and disheartened, our correspondent adds.
Mr Reid said the Republicans had "repeatedly chosen to protect the Republican administration rather than get to the bottom of what happened and why" in the run-up to the war.
He said the indictment of Mr Libby showed how the administration of President George W Bush had manufactured and manipulated intelligence in order to justify the 2003 invasion.
Mr Libby has been charged with obstructing justice, perjury and making false statements to a federal grand jury, in a case stemming from the leaking of the identity of a CIA agent, which has also touched on the Iraq war.
Democrats contend that the unmasking of Valerie Plame, the CIA official, was retribution for her husband, Joseph Wilson, publicly challenging the Bush administration's contention that Iraq was seeking to purchase uranium from Africa.
The claim was part of the White House's justification for going to war.