BEIJING (AP) _ Police in eastern China have again detained a former policeman recently released from a three-year prison sentence for helping farmers organize a tax protest, a civil rights group said Saturday.

The action apparently was prompted by Guo Shaokun's threat to travel to China's commercial capital Shanghai to protest the revocation of his police benefits, said the Hong Kong-based Information Center for Human Rights and Democracy.

Over the next week, Shanghai will host the Asian Pacific Economic Cooperation forum's annual meeting, to be attended by leaders such as Chinese President Jiang Zemin and President Bush.

Guo was taken from his home in the industrial city of Xuzhou north of Shanghai on Friday night and has not been heard of since, the center said. It said his family's telephone connection was also cut.

Guo lost his subsidized food and housing and other privileges after being sentenced in 1999 for helping the farmers, it said. Such protests have become increasingly common as farmers chafe under the burden of high taxes and sundry other fees, many of them illegal, charged by local authorities. The center did not say what crime Guo had been convicted of, but such actions are often prosecuted under sweeping state security laws.

A Xuzhou police spokesman who declined to give his name said he had no information about Guo.