Pope John Paul told thousands of pilgrims gathered in St Peter's Basilica in the Vatican today that their offerings would be donated to help ease the plight of people in Iraq.
"It is my wish that the offerings collected during this celebration go towards alleviating the urgent needs of those who are suffering in Iraq due to the war," the pope said.
As the focus of the Iraq war switched from fighting to humanitarian operations, aid has started to flow into the country but officials have warned time is running out.
The pope led a vigorous anti-war campaign ahead of the US-led attack. Since Baghdad was seized, the Vatican has urged a quick end to the conflict and offered to help coordinate humanitarian assistance through its Iraqi dioceses.
During the mass on Thursday night to recall Christ's Last Supper with his apostles, the pope said that "those who participate in this mass cannot remain indifferent when faced with the expectations of the poor and those in need".
In both the morning and the evening masses, the 82-year-old pontiff used a new mobile throne to move up and down the main aisle and a small lift to reach the main altar to help him conserve his strength in the run-up to Easter Sunday.
For the second year running, two cardinals also stood in for him to wash and kiss the feet of 12 priests in a gesture commemorating Christ's gesture of humility to his apostles the night before he died.
The innovations were introduced to help the pope keep strain off his right leg, which he broke in a fall nine years ago and which has since been afflicted by arthritis.
Holy Thursday marks the start of four days of hectic activities for the pope which culminate on Easter Sunday, when he delivers his twice-yearly "urbi et orbi" (to the city and the world) blessing and message.
On Holy Thursday, Christians commemorate the day Christ founded the priesthood.
The pope also signed his latest encyclical which says that Church regulations generally forbidding Protestants and Catholics from taking communion together had to be respected.
The reaffirmation of the standing rule also affects Anglicans including British Prime Minister Tony Blair. Years ago, he was said to have taken communion in a Catholic Church with his wife who is Catholic.