As a yet new evidence of how wellthe US-Iraqi Baghdad security plan is proceeding, UN chief Ban Ki-moon flinchedafter a powerful blast sent shock waves through a building where he was givinga news conference.

"I'm confident that we'll be able to see, inthe near future, a more prosperous and secure... and a healthier future of theIraqi people and government," Ban told a joint press conference with IraqiPrime Minister Nuri al-Maliki, reported Agence France-Press (AFP).

Before he even finished the sentence, a mortar blastrocked Baghdad'sfortified Green Zone where the conference was being held.

Ban, on his first visit to Baghdad which was unannounced, ducked,grimaced and hurriedly pocketed his notes.

Maliki, whose live televised events have been disruptedby bomb attacks in the past, appeared unruffled.

Seconds later, the UN chief recovered his composureand took one further question from a journalist before leaving the conferenceroom.

The loud blast sent a column of smoke and dust intothe sky near the northern edge of the Green Zone, which hosts the US embassy andthe seat of the Iraqi government.

An Iraqi security official said the explosion hadbeen caused by a mortar shell fired into the area. There were no initialreports of casualties.

US and Iraqi troops are waging a massive securityoperation that will see 25,000 extra troops deployed in a bid to control Baghdad and quell deadlysectarian warfare.

On Thursday the USmilitary announced that three more American soldiers had been killed in Iraq, bringingthe latest deaths in the four years since the invasion to 3,225, according toan AFP tally based on Pentagon figures.

Secret

Ban's presence was only made public after he toucheddown in Baghdadon the first leg of his first major overseas tour since taking office threemonths ago.

He was quickly ushered into talks with Maliki.

"He will be meeting with parliament members andhe will be meeting different political groups' leaderships and the diplomaticcorps," local UN spokesman Said Erekat told AFP before the new conference.

It was not immediately clear if the UN chief'sagenda would be affected by what happened.

Aides said one of Ban's priorities during his Middle East tour will be the UN role in the Iraq Compactfor economic development, just one week after the United Nations hosted aninternational conference focused on the country.

The International Compact with Iraq (ICI) initiativebetween Iraqand the international community was established in July with World Bank support.

Last Friday, Vice President Adel Abdel Mahdi laidout a five-year economic revival plan before nearly 90 countries which willreview Iraq'sprogress in carrying out reforms in exchange for international aid and debtrelief.

Ban's trip was the first by the top UN officialsince his predecessor, Kofi Annan, visited in November 2005.

The United Nations has been operating in Iraq at greatlyreduced levels since international staffers were withdrawn following an attackon their headquarters.

A bomb at the UN headquarters in Baghdad on August 19, 2003, killed 22 people,including top UN envoy Sergio Vieira de Mello.

Source:Agencies