UN Secretary-General Ban Ki-moon (Oct 2009 file photo)The U.N. Secretary-General is condemning the terrorist attack that killed five World Food Program aid workers in Islamabad, Pakistan. Several other people were injured in the attack as well.  

Islamabad police say a suicide bomber disguised as a security officer struck the lobby of the WFP headquarters in Pakistan shortly after midday.  Some of the injured, who are in critical condition are being treated in a hospital.

The U.N. Secretary-General, Ban Ki-moon is in Geneva for the opening of the World Telecom Conference. He says his mood of high expectations and happiness has been transformed into a heavy mind and sadness with the news of the terrorist attack in Islamabad.

"I condemn in the strongest terms the attack at the Office of the World Food Program in Islamabad, Pakistan," Ban said. "Such an attack is unjustifiable. This is a terrible tragedy for the United Nations and the whole humanitarian community in Pakistan. This is a heinous crime committed against those who had been working tirelessly to assist the poor and the vulnerable on the front-lines of hunger and other suffering in Pakistan."  

Pakistani paramilitary soldiers patrol in front of the United Nations office after a suicide blast in Islamabad, 05 Oct 2009Mr. Ban said he offers his deepest condolences to the colleagues who fell in the line of duty for noble causes and to their families and friends.

WFP Executive Director Josette Sheeran issued a statement expressing her deepest condolences and called the victims humanitarian heroes.

Militants have mounted numerous suicide attacks in Pakistan during the past two-and-one-half years. Several of them targeted foreigners.

U.N. chief Ban says humanitarian assistance to the Pakistani people will continue despite this tragedy.

"There are more than two million displaced persons who need urgent humanitarian assistance. They need our assistance," he said. "They are very vulnerable people. We have to help them so that they can be reintegrated and they can return to their own homes. That is our commitment and we will continue."  

The World Food Program is providing vital food assistance to about 10 million people across Pakistan. This includes emergency relief to as many as two-million Pakistani civilians who fled conflict in the Swat Valley region earlier this year.  

The United Nations says it is closing its offices in Pakistan temporarily, while it assesses the security situation.