Chinese police have briefly released a jailed U.S.-based businessman, but then put him into a hospital where his lawyer says he is once again under guard. The attorney says the actions may be related a visit to the Chinese capital by a group of U.S. senators.

An American lawyer who represents Liu Yaping says his client was released Wednesday from a military detention center in Inner Mongolia, long enough to get a haircut and have dinner with family members.

But attorney Jerome Cohen says Mr. Liu was then taken to a hospital, and is back in confinement. In a VOA interview, Mr. Cohen says the unexplained actions may be designed to deflect questions about Mr. Liu's case by a U.S. delegation headed by Senator Joseph Biden, that is currently holding talks in Beijing.

News of Liu's renewed detention surprised Mr. Biden Thursday, who said he would raise the issue in planned meetings with top Chinese officials. Senator Fred Thompson said this and other detentions and releases appear to be a thinly disguised efforts designed to manipulate the U.S. officials.

Last month, China released three scholars with U.S. links before a visit by U.S. Secretary of State Colin Powell. Chinese courts had convicted the scholars of spying.

Mr. Liu is a Chinese citizen and a permanent U.S. resident who is married to a U.S. citizen. He was detained in the northern Chinese region of Inner Mongolia in March as police investigated allegations of tax evasion and fraudulent financial practices.

One of Mr. Liu's attorneys tried to meet with him on Thursday, but was blocked by local officials.

Mr. Cohen says that is a violation of a Chinese law that guarantees defendants access to legal assistance. The attorney is calling for an investigation into the case by China's central government, unless Mr. Liu is sent to Beijing or the United States for medical treatment.

So far, there has been no official Chinese comment on the latest developments in this case.