Oslo, Norway ? Finnish mediator Martti Ahtisaari accepted this year’s Nobel Peace Prize with a plea to President-elect Barack Obama: Start pressing for Middle East peace as soon as you can.

Receiving the coveted award in Oslo, the former Finnish president rejected the notion that “the Middle East knot can never be untied” and criticized world leaders — as well as the Israelis and Palestinians — for letting the violence continue.

“The international community and those in power are sitting there letting them destroy each other,” Ahtisaari, 71, told The Associated Press in an interview before Wednesday’s prize ceremony. “They are allowing both parties to make their lives in the future even more complicated and difficult than it is today.”

He reiterated that call in his acceptance speech, with a special message to Obama.

“I do 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 the office,” he told dignitaries at Oslo’s City Hall.

Obama has pledged to make progress on the Israeli-Palestinian conflict a key diplomatic priority. He has called for a sustained push to achieve the goal of two states, a Jewish state in Israel and a Palestinian state, that can exist in peace and security. He has also pledged to end the Iraq war and employ diplomacy more often than President George W. Bush.

Decades of peace work

Ahtisaari received this year’s coveted Nobel Peace Prize for his three decades of peace work spanning three continents.

He was a senior Finnish diplomat when in 1977 he was named the U.N. envoy for Namibia, where guerrillas were battling South African apartheid rule. He later became undersecretary-general, and in 1988 was dispatched to Namibia to lead 8,000 U.N. peacekeepers during its transition to independence.

“No single diplomat did more than he did to deliver Namibia’s independence,” committee chairman Ole Danbolt Mjoes said.

After serving as Finnish president 1994-2000, Ahtisaari returned to peace efforts in Kosovo and in Indonesia, where he negotiated a 2005 peace deal between the government and Aceh rebels.

Ahtisaari, who founded the Crisis Management Initiative, a mediation group, has not sought a role in the Middle East, saying the process was already in good hands with former British Prime Minister Tony Blair mediating.

“It’s difficult if you have too many cooks in the kitchen,” he said.

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

In his speech, Ahtisaari insisted that wars and conflicts are not inevitable.

“Peace is a question of will. All conflicts can be settled and there are no excuses for allowing them to become eternal,” he said.

He also warned the global financial crisis would strike hard at the developing world, and urged governments to not cut back on foreign aid.

The peace prize ceremony was in Oslo, while the Nobel awards in medicine, physics, chemistry, literature and economics were presented in the Swedish capital, Stockholm, in line with the 1895 will of prize founder Alfred Nobel.

Other Nobel winners

U.S. economist and New York Times columnist Paul Krugman accepted the Nobel Memorial Prize in Economic Sciences for his analysis of how economies of scale can affect international trade patterns.

The medicine prize cited French researchers Francoise Barre-Sinoussi and Luc Montagnier for their discovery of human immunodeficiency virus, or HIV, in 1983. They shared the award with Germany’s Harald zur Hausen, who was honored for finding viruses that cause cervical cancer.

Japan’s Osamu Shimomura and Americans Martin Chalfie and Roger Tsien shared the chemistry prize for discovering and developing a fluorescent protein, while Japanese scientists Makoto Kobayashi and Toshihide Maskawa split the physics award with American Yoichiro Nambu for research on the smallest particles of matter. Nambu, 87, canceled his trip to Stockholm for health reasons and was to receive his award at a ceremony in Chicago.

The Swedish Academy continued a trend of honoring European writers by selecting Frenchman Jean-Marie Gustave Le Clezio for the literature prize. The author of more than 40 works including “The Book of Flights” and “Desert,” Le Clezio holds dual nationality with Mauritius and spends much of his time in Albuquerque, New Mexico.

The prizes — including a $1.2 million purse, a diploma and a gold medal — are always handed out on Dec. 10, the anniversary of Nobel’s death in 1896.