BEIJING (AP) _ Chinese authorities have detained two dissidents and placed a third under surveillance in a widening police sweep against members of a would-be opposition party, rights groups reported today.

Two of the dissidents _ Xie Wanjun and Liu Lianjun _ reported receiving encouraging signals from the government earlier this month about setting up the China Democracy Party. But last week police began detaining and interrogating people connected to the party.

Authorities in eastern Shandong province detained Xie on Monday, the U.S.-based Chinese Democratic Justice Party reported.

In another detention, police in Bengbu, a city in eastern Anhui province, took Wang Hongxue from his home Monday night and told his family today to send him clothes, the Hong Kong-based Information Center of Human Rights and Democratic Movement said.

Liu, who was detained briefly Saturday, now had five police officers watching his home in the Shandong city of Weifang, the group said.

Dissidents have been trying to register the China Democracy Party with the government since President Clinton visited China in June. The ruling Communist Party has never allowed a new opposition party to form since taking power in 1949.

Xie and Liu had said they felt encouraged when they tried to register the party with the Shandong provincial office of the Ministry of Civil Affairs. Officials did not immediately reject their application but rather explained requirements for setting up a legal organization, according to accounts by human rights groups.

However, police in the northeastern city of Changchun have indicated the China Democracy Party already has been ruled illegal. On Friday, they arrested dissident Tang Yuanjuan, who had traveled to several cities on behalf of the party. He was accused of having contacts with an illegal organization.

Today, 179 Chinese dissidents sent an open letter to President Jiang Zemin and Premier Zhu Rongji protesting the detention of Tang and other dissidents.