Former world chess champion Bobby Fischer (search), who was taken into custody by Japanese authorities two weeks ago for traveling with a revoked U.S. passport, has appealed a deportation order to the United States, an adviser said Monday.

The American chess player, wanted by U.S. authorities for playing a 1992 match in the former Yugoslavia in violation of international sanctions, was granted a three-day extension Friday to contest Japan's decision last week to deport him.

Fischer's lawyer filed the appeal with immigration authorities at Narita international airport (search), where Fischer is being held, said John Bosnitch, a Tokyo-based communications consultant advising Fischer.

The deadline for the appeal — addressed to Japan's justice minister — was midnight Monday, and a decision typically takes two to three weeks, Bosnitch told The Associated Press.

"If there is some move to railroad this along before that, we'll ask a court for an injunction" to stop the immigration proceedings, Bosnitch said. Fischer maintains the proceedings are illegal.

The filing was Fischer's latest attempt to avoid possible U.S. prosecution. In the United States he would face up to 10 years in prison and a maximum fine of $250,000, officials say.

Justice Ministry official Shoichi Okabe declined to comment on the filing, citing privacy laws. He said there's no set timeframe for a decision, because every appeal is considered on a case-by-case basis.

It was the second time Fischer has appealed the deportation order; the first, made verbally at a hearing, was rejected last Tuesday.

Fischer's chances of winning the appeal remain unclear, but the proceedings will likely stall his handover to U.S. officials. Bosnitch said Fischer's lawyer was prepared to make two more filings as early as Tuesday — one request for refugee status, another for temporary release in Japan.

Fischer was caught at Tokyo's Narita airport July 13 trying to board a plane for the Philippines with a passport that had been revoked by the United States. Tokyo had prepared to deport him, but Fischer appealed, claiming his passport was revoked in November without due process and should still be valid.

Since his detention, supporters of Fischer have prepared for him to apply for a German passport based on his father's German citizenship. They also have sought political asylum for him in a third country.

On Monday, an adviser to Montenegro's president, Filip Vujanovic, said the central European nation was willing to offer Fischer a safe haven.

"Montenegro will have a positive attitude toward a request by the former world champion for asylum here," Radmila Buric said.

Bosnitch said the announcement was expected.

"I initiated it, so it comes as no surprise," Bosnitch said, adding that he and other Fischer supporters had contacted "several" countries.

"As you can see, this process is moving forward," he said, without elaborating.

Supporters say Fischer is being held as a "political prisoner" for anti-American views he expressed in the Philippines after the Sept. 11 terror attacks in the United States.

Fischer — considered by some to be the world's greatest chess player — became a legend when, at the height of the Cold War, he defeated the former Soviet Union's Boris Spassky (search) in a series of games in Reykjavik, Iceland, in 1972 to claim the world championship.

Known for erratic behavior at matches, he became a recluse for years until he resurfaced for the fateful match against Spassky in Yugoslavia.

Fischer won the match, and more than $3 million in prize money, but he played in violation of U.N. sanctions and has since been wanted in the United States.