Prime Minister Shinzo Abe is taking a big gamble by trusting North Korea, the world’s most isolated nation and one with a notorious record of betrayal and delaying tactics designed to elicit greater concessions.

In a potential breakthrough, Pyongyang has agreed to reinvestigate the fates of Japanese who vanished in North Korea, including those suspected of being abducted by its agents, Abe said Thursday.

In return, Tokyo has pledged to lift certain economic sanctions if the investigation begins and may even extend economic assistance to Pyongyang if the probe generates tangible results, according to the bilateral agreement signed and released on Thursday.

But many fear the North’s apparent readiness to cooperate may be just another tactic to ease its international isolation and secure economic aid. If the Abe administration makes a compromise that is poorly thought through and ends up giving Pyongyang cash, observers say that Abe will likely be in trouble.

“The Japanese side took a bold step, although the prospect is not clear at all,” said Masao Okonogi, a professor at Kyushu University who is a noted Korea expert.

“If, say, only one (abductee) is returned, the Abe administration would face severe criticism at home. It’s a big risk for the prime minister,” Okonogi said.

For example, Pyongyang agreed in 2008 to open an investigation into Japanese thought to have been kidnapped by its agents, but later reneged on the promise.

On Friday, the Mainichi Shimbun reported that Pyongyang has suggested it might return some other Japanese who went missing in North Korea but who are not on Japan’s official list of 12 outstanding abductees.

Tokyo maintains that at least 17 Japanese nationals were kidnapped in the 1970s and ’80s and suspects that dozens more suffered a similar fate.

Five returned to Japan in 2002, thanks to the diplomatic efforts of then Prime Minister Junichiro Koizumi. Pyongyang has claimed the rest either died or never arrived in the first place.

Tales of the abductees’ horrifying ordeals, some were taken as children, has kept their plight in the public eye, and recovering them has been a priority of past administrations.

Abe’s tough nationalist rhetoric on the abductions issue vaulted him into his first, short-lived stint in office in 2006.

But Japanese officials say that this time, Pyongyang may be serious, pointing out that the North “swallowed” a number of Tokyo’s demands for the written agreement.

A senior government official said Abe now believes he has a chance to settle the abduction issue once and for all.

Pyongyang’s ties with Beijing, its largest trade partner and sole major political ally, have plunged this year.

The Chosun Ilbo, a major South Korean daily, has reported that China exported no oil to North Korea in the first four months of this year. If true, this will inflict severe damage on the North’s ailing economy.

Hajime Izumi, a Korea expert at University of Shizuoka, said Pyongyang probably fears Beijing will abandon it and instead build closer ties with South Korea, which held a summit with China last year, leaving Japan on the waiting list.

This concern may have prompted Pyongyang to improve ties with Japan, he said.

“For it to improve its economy, it needs good relations with South Korea, Japan and the U.S. This is clear,” he said.

Japanese officials remain cautious, given Pyongyang’s notorious record on promises, especially those made in exchange for economic aid.

Chief Cabinet Secretary Yoshihide Suga has emphasized that sanctions will not be lifted until Tokyo confirms Pyongyang has started the reinvestigation.

The text of the agreement declares that Tokyo will “consider” providing humanitarian aid to North Korea “at an appropriate time.” But Suga stressed Japan will not provide aid unless the probe makes progress.

And Suga has also said Tokyo may shelve plans to lift sanctions if the North fails to meet up to expectations.

“Right now we have no plan (to provide aid), and we will consider it after seeing how the investigation is going,” Suga said.