SEOUL, South Korea -- The sentencing of two American journalists to 12 years' hard labor in North Korea on Monday sets the stage for possible negotiations with the nation for their release, perhaps involving an envoy from the U.S.

New Mexico Gov. Bill Richardson, who helped win the release of Americans from North Korea in the 1990s, said he was "ready to do anything" the Obama administration asked. Another possible negotiator, if the U.S. government approved, is former vice president Al Gore, who founded the TV venture the reporters work for.

A senior Obama administration official said Richardson and Gore had been in contact with the White House and State Department about potential next steps, including possibly sending an envoy to try to negotiate the release of Euna Lee, 36, and Laura Ling, 32.

The official said no decisions had been made on how to proceed and that neither Gore nor Richardson had been asked to go. The official spoke on condition of anonymity due to the diplomatic sensitivity of the situation.

The North Korean regime is probably less interested in having the women sent to its gulag, where poorly fed inmates often do backbreaking work in factories, coal mines and rice paddies.

Instead, Pyongyang will likely try to use them as bargaining chips in an increasingly tense standoff with the U.S. over the North's recent nuclear and missile tests.

President Barack Obama "is deeply concerned by the reported sentencing of the two American citizen journalists by North Korean authorities, and we are engaged through all possible channels to secure their release," said deputy White House spokesman William Burton.

Richardson said the journalists were part of a "high-stakes poker game" North Korea is playing, and that now the legal process has been completed, he thinks talks for their release can begin, with some kind of a political pardon as a goal.

"In previous instances where I was involved in negotiating, you could not get this started until the legal process had ended," he said on NBC's "Today" show.

Richardson said officials of the Obama administration had been in contact with him for his thoughts on how to proceed. Asked by CNN if he would be willing to go to Pyongyang on behalf of the Obama administration, Richardson replied: "If they asked for my help, of course, I'd be ready to do anything. But this is something that is very sensitive at this stage."

He said the sentence was harsher than expected, but added that the fact that espionage was not mentioned was a good sign.

He said North Korea so far has not, at least publicly, tried to tie this incident to differences with Washington over its nuclear program and the recent series of missile tests that it has conducted. He also said he has not seen particularly bellicose rhetoric from Pyongyang on the issue of the two women.

For several days, rumors have been swirling that Gore would fly to North Korea to negotiate the reporters' release. But Gore has not commented on a possible trip and has stayed silent about the case in general.

Victor Cha, who served as a senior Asia adviser on former president George W. Bush's National Security Council, said a high-level envoy, such as Gore, should be sent to negotiate the release of the Americans.

"North Koreans care a great deal about public face, and sending someone of Gore's stature would be an eminently credible humanitarian mission," he said.

North Korea wants to be treated like a legitimate nuclear state and hopes to draw Washington into direct negotiations about normalizing relations. Washington has refused to endorse such a status for an unpredictable nation with a history of terrorism, ripping up agreements and sharing its nuclear know-how with nations hostile to America.

Pyongyang is believed to be preparing another long-range missile test at a new launchpad. On Monday, North Korea warned fishing boats to stay away from the east coast, Japan's coast guard said, feeding concerns that more missile tests are being planned.

The U.N. has also been debating a new resolution to punish the North for its second nuclear test May 25. Pyongyang followed the test with a barrage of missile launches.

The case gives the two sides an excuse to talk, with the U.S. possibly sending a special envoy, said Kim Yong-hyun, a professor at Seoul's Dongguk University.

"I think the North is going to try to use the reporters to facilitate relations with the U.S.," said Kim, adding that he didn't think the women would be mistreated and would even be kept separate from North Korean inmates.

"The sentence doesn't mean much because the issue will be resolved diplomatically in the end," Kim said.

The journalists were arrested March 17 near the China-North Korea border, and it's unclear whether they tried to sneak into the North or if aggressive border guards crossed into Chinese territory and grabbed them, as has happened before. A cameraman and their local guide escaped.

The North accused the reporters of unspecified "hostile acts" and illegally entering the country, but the formal charges against them were unclear. Their trial began Thursday and foreigners weren't allowed to observe the proceedings.

The North's official news agency said Monday the women committed a "grave crime" and would be sentenced to 12 years of "reform through labor."

State Department spokesman Ian Kelly said U.S. officials do not know details of the charges against the two or the exact location of their confinement.

"We plan to explore all possible channels," Kelly said without being specific. "As we have all along, we call on the North Korean authorities to release the two young ladies."

Ling's father, Doug Ling, told The Associated Press at his home in the Sacramento, Calif., suburb of Carmichael that the family will "keep a low-profile until we hear something better about the situation."

Earlier, spokeswoman Alanna Zahn said the families of Lee and Ling -- sister of TV reporter Lisa Ling -- had no immediate comment about the sentencing. Ling is an ethnic Chinese, while Lee is of Korean descent and speaks Korean.

Lisa Ling has said the reporters never intended to cross into North Korea, and she said her younger sister suffered from an ulcer requiring medical treatment while Lee is the mother of a 4-year-old, Hannah.

The International Women's Media Foundation condemned the conviction, and the group's executive director, Liza Gross, said in a statement that "press freedom must not be used as a pawn in chess games between nations."

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Foreman reported from Seoul, Lee from Washington. Associated Press writers Jae-soon Chang, Hyung-jin Kim and Vijay Joshi in Seoul, Shino Yuasa in Tokyo, Carley Petesch in New York and Judy Lin in Carmichael, Calif., contributed to this report.