The International Committee of the Red Cross has urged the opposing sides in the war in Iraq to abide by the Geneva Conventions governing the conduct of warfare.
Speaking shortly after the United States launched a military strike on Baghdad, the ICRC president told a news conference in Geneva that even in wars people had rights that must be respected.
"The impact of war is always dramatic, particularly on civilians," Kellenberger said. "The priority now must be to protect the lives and the dignity of victims of this war."
"The ICRC has reminded the governments of Iraq, the United Kingdom and the United States of their obligations under the Geneva Conventions, which they have all signed."
Kellenberger recalled that it was prohibited under the Conventions to direct attacks against civilians, and he urged the warring parties to take every precaution to spare the civilian population.
"There are limits to warfare," Kellenberger said. "Indiscriminate attacks are prohibited, as are threats or acts of violence, the primary purpose of which is to spread terror among the civilian population.
He reminded the countries involved in the conflict that use of biological and chemical weapons was not permitted.
Kellenberger told swissinfo he had learned of the start of the US military campaign from his delegates in Iraq.
"The present team are ten delegates and more than 100 national ICRC staff, but we have dozens of other delegates in Kuwait, Iran and Jordan."
Kellenberger said preparations had been made for the outbreak of war and ICRC delegates intended to stay in place in Iraq for the duration of the fighting, carrying out humanitarian operations.
"It is essential that we carry out our humanitarian tasks," he said and issued an appeal to the warring parties to protect his staff in Iraq and allow them to carry out their work.
"Red Cross and Red Crescent emblems, and those working under them, must be protected."
swissinfo, Imogen Foulkes