Tonight... Get on the record!

A huge explosion in Baghdad today ripped through U.N. headquarters in Iraq, killing at least 20 people and wounding more than 100 others.  

The work was apparently carried out by a homicide bomber driving a truck filled with explosives.

The bomber apparently drove the truck into the lobby of the Canal Hotel, where the headquarters was located, before the bomb went off.

By U.N. estimates, there are at least 300 people who usually work in the building.

Among those killed by the blast, the top U.N. official Sergio Vieira de Mello (search) in Iraq who was trapped in the rubble. 

President Bush (search) condemned the attack on the U.N. headquarters in a statement from his ranch in Crawford, Texas.

The president called the attackers, "enemies of the civilized world" and vowed "these killers will not determine the future of Iraq."

We'll have the latest on this developing story including LIVE reports from Iraq this evening.

FOX News Channel Contributor and former House Speaker Newt Gingrich will also join Greta to discuss how the bombing may alter U.S. policies in Iraq.

Also, UPI Editor-at-Large Arnaud de Borchgrave will share his analysis of the situation.

Get on the record tonight at 10 p.m. ET only on the FOX News Channel!

-- The Associated Press contributed to this report.

Note: Topics and guests are subject to change