Updated

About 400 United Nations staff, many in tears, held a memorial service for Nadia Younes, a senior U.N. official who was killed in the bomb attack on U.N. offices in Baghdad.

Younes, a 57 year-old Egyptian who had worked for the United Nations for more than 30 years, was in Iraq as chief of staff for U.N. envoy Sergio Vieira de Mello. He also died in Tuesday's explosion, which claimed at least 23 lives and injured more than 100.

"She was an amazing person — full of life, energetic and extremely resourceful," World Health Organization director-general Jong-wook Lee said of Younes during Thursday's memorial.

Younes was the head of external relations at the WHO and had been on assignment in Iraq since May.

She joined the WHO in August 2002 and before that was the main spokeswoman for the U.N. field mission in Kosovo, and earlier U.N. chief of protocol in New York.

She was one of the main U.N. spokespeople under former U.N. Secretary-General Boutros Boutros-Ghali from 1988 to 1993.

Egyptian ambassador Naela Gabr described Younes' death as a "loss not just to Egypt but to the international community."

"We are shocked, concerned and saddened," said Isabelle Nuttal of WHO's staff association. "Her colleagues will always remember her hearty laughter, her availability and extraordinary interaction with teams. Nadia carried the ideals of the United Nations like a sacred flame."