The United States launched a military strike against Iraq on Wednesday night after President Bush's deadline for Saddam Hussein to surrender power passed unheeded.
"The opening stages of the disarmament of the Iraqi regime have begun," White House press secretary Ari Fleischer said.
Bush planned to address the nation at 10:15 p.m. EST, little more than two hours after the deadline the president set for Saddam Hussein to flee his nation or face war.
Fleischer spoke as anti-aircraft fire and explosions were heard across Baghdad after air raid sirens went off at the capital at dawn.

MOTION SUBMITTED TO PARLIAMENT SPEAKER'S OFFICE
ANKARA - Prime Ministry motion on sending Turkish troops to northern Iraq and opening Turkish airspace to aircrafts of foreign armed forces for six months was presented to the Parliament Speaker's Office late on Wednesday.
Recalling that U.S. technical and military personnel had been allowed to stay in Turkey for three months for modernization of bases and ports to be used in a possible military action against Iraq, the motion said, ''latest developments regarding military action against Iraq show that it has reached a point of no return. All efforts for a peaceful solution failed after the United Nations process was exhausted, and a military action has become inevitable. At the current stage, Turkey faces conditions of war in which Iraqi territories will completely turn into battlefield. As a result, threats and risks against Turkey's security have reached worrying dimensions.''
''Within this framework, it is seen that PKK/KADEK terrorists who take shelter in northern Iraq have accelerated their acts and have been trying to take new positions in order to make use of crisis atmosphere. Besides, it is seen that efforts which have been expended to create grounds for political formations that would cause division of Iraq on ethnic basis, have been intensified. This situation brings along the risk of endangering Iraq's territorial integrity and creation of an environment of instability that may threaten safety of other national groups in the region,'' the motion said.
The motion said that plans had been made, and final preparations for rapid activation of crisis management mechanisms were finalized by taking into consideration the possibility of a huge migration wave into Turkey.
''Maintaining an effective dissuasiveness against these negative developments that pose serious threat potential against Turkey's security depends on our active military existence in northern Iraq. Similarly, taking necessary measures in a forward line for prevention of migration necessitates our military existence in the region,'' it said.
''The aim and function of dissuasive military existence of Turkey in northern Iraq will be limited with these basic targets. Unless it is obliged to do it, the Turkish Armed Forces won't clash with Iraqi Armed Forces, and it will be deployed in the region in line with this. Similarly, our temporary military existence in the region will also constitute an assurance for safety of national groups in northern Iraq,'' it noted.
Stressing that taking a decision on support and facilities to countries that would join military action for disarmament of Iraq in line with U.N. Security Council resolutions, had gained importance, it said, ''with this respect, many countries, particularly NATO allies have permitted allied air forces elements to use their airspace with this objective.''
''Consequently, the 59th government reached a conclusion that it would be appropriate for the parliament to authorize the government with taking decisions on sending Turkish Armed Forces to northern Iraq and opening Turkish airspace to air elements of foreign armed forces for six months,'' it added.
The government motion will be debated in the parliament on Thursday.
(MS) 20.03.2003