Nobel Peace Prize winner Martti Ahtisaari urged U.S. President-elect Barack Obama on Wednesday to start his term by giving high priority to the Middle East conflict, calling it the world's most challenging peace-building project.

In his acceptance speech in Oslo, the Finnish diplomat and mediator also warned that the global financial crisis would strike hard at the developing world, and called on governments to not cut back on foreign aid.

Insisting that all conflicts can be settled, Ahtisaari said he did not share the view that the decades-long violence between Israel and Palestinians would rage indefinitely.

"Many have come to believe that the Middle East knot can never be untied. I do not share this belief," Ahtisaari said in his acceptance speech. "All crises, including the one in the Middle East, can be resolved. The solution would require a contribution from all the parties involved as well as the international community as a whole."

The 71-year-old former Finnish president was awarded what many consider the world's most coveted prize for his three decades of work mediating conflicts from Namibia to Kosovo and Indonesia. So far he has not sought a role to mediate in the Middle East.

"I hope that the new president of the United States, who will be sworn in next month, will give high priority to the Middle East conflict during his first year in office," Ahtisaari said.

In an interview with The Associated Press before the award ceremony, he criticized world leaders for not doing enough to solve the Israeli-Palestinian conflict.

"The international community and those in power are sitting there letting them destroy each other and they are allowing both parties to make their lives in the future even more complicated and difficult than it is today," he said.

In Wednesday's prepared remarks, the skilled and dogged negotiator said he could not accept religious tensions as a reason for the intractability of the bloodshed in the Middle East. "Religions," he said, "are peace-loving and can be a constructive force in solving conflicts. That also applies to Mideast peace efforts, which he called the most challenging peace-building project ahead of us."

By selecting Ahtisaari for the prize, the Nobel committee returned its focus to traditional peace work after tapping climate campaigner Al Gore and the UN panel on climate change last year.

"His efforts have been untiring, and he has achieved good results," committee chairman Ole Danbolt Mjoes said of Ahtisaari in prepared remarks. Ahtisaari was a senior Finnish diplomat when in 1977 he was named the UN envoy for Namibia, where guerrillas were battling South African apartheid rule. He later rose to undersecretary-general, and in 1988 was dispatched to Namibia to lead 8,000 UN peacekeepers during its transition to independence.

He served as Finland's president from 1994 until declining re-election in 2000, when he left politics and founded his Crisis Management Initiative, a peace mediation institute. His peace efforts continued, in Kosovo and in Indonesia, where he negotiated a 2005 peace deal between the Indonesian government and rebels in Aceh province.

Ahtisaari warned that the effects of the financial crisis could prove another major setback for poor countries already hit hard by climate change, rising food prices and declining levels of foreign trade.

"A reduction in foreign assistance and investment would be disastrous for badly needed economic growth," he said. "At this difficult time I call on all governments to remain committed to their stated goals of eradicating poverty."

The Nobel prizes are always presented on Dec. 10, the anniversary of the death of their founder, Swedish industrialist Alfred Nobel. The peace prize is presented in Oslo, and the prizes in medicine, physics, chemistry, economics and literature in Stockholm, Sweden.