By Brian Ellsworth

CARACAS (Reuters) - A former Guantanamo prisoner who was relocated to Uruguay nearly two years ago is being held by Venezuela's intelligence agency after traveling to Caracas in an apparent attempt to reunite with family, a lawyer familiar with his case said on Tuesday.

Jihad Diyab was held for 12 years in Guantanamo without being charged and was released to Uruguay in 2014 as part of an arrangement to reduce the number of detainees at the U.S. military prison, according to California-based lawyer Jon Eisenberg.

The Syrian national was not seen in Montevideo after mid-June and arrived in Caracas on July 26, Eisenberg said in a telephone interview. At that point Diyab asked the Uruguayan consulate to help him travel to Turkey where he was to meet with his family.

Diyab was then arrested by Venezuelan security forces and has been held by the Sebin intelligence service without access to lawyers or visitors since approximately July 30, Eisenberg said.

"I have not been able to make contact with him and have gotten no official response from the Venezuela government as to why he is being detained or where," said Eisenberg, who represented Diyab in a court challenge to a U.S. Defense Department policy of force-feeding Guantanamo prisoners that went on hunger strike.

The Venezuelan Information Ministry, which frequently handles media requests on behalf of other state agencies, did not respond to an email seeking comment.

Reuters was unable to obtain comment from the office of Venezuela's vice president, which oversees Sebin.

Eisenberg stopped representing Diyab after he was released but has been advising him regarding ongoing efforts to secure the public release of videos showing Diyab being violently force-fed while he was in Guantanamo.

News that Diyab had left Uruguay led a group of U.S. lawmakers to demand that President Barack Obama halt transfers of Guantanamo prisoners, arguing that they represented a security risk to Americans.

Diyab was captured in 2002 near the border region of Afghanistan and Pakistan and transferred to Guantanamo, according to a letter written in July by a group of U.S. Senators, who described him as a "weapons smuggler."

Venezuela's government, which has been an ideological adversary of the United States since the 14-year rule of late socialist leader Hugo Chavez, has been harshly critical of U.S. treatment of Guantanamo prisoners.

Chavez in 2009 said Venezuela would be willing to receive Guantanamo prisoners as part of efforts to help close the prison and return the land housing the U.S. Naval Base in Guantanamo Bay, Cuba, to the government of Cuba.

(Reporting by Brian Ellsworth; Editing by Tom Brown)