In a nearly 90-minute news conference aired on tape-delay on state television, Mr. Maliki defied his rivals and pushed back on all fronts in Iraq’s burgeoning political crisis, threatening to release investigatory files that he claimed show his opponents have been involved in terrorism.

He told Kurdish leaders that there would be “problems” if they do not turn over Vice President Tariq al-Hashemi, who fled to the semi-autonomous Kurdish region in recent days to escape an arrest warrant on charges he ran a death squad responsible for assassinations and bombings.

The Iraqi leader, a Shiite, also issued a warning to his rivals from Iraqiya, the largely Sunni bloc of lawmakers that includes Mr. Hashemi: if it does not end its boycott of Parliament and the Council of Ministers, he would move to form a majority government that would, in essence, exclude them from power.

If Iraqiya’s ministers do not show up at future sessions, he said, “we will appoint replacements.”