Joran van der Sloot, the prime suspect in the 2005 disappearance of Alabama teenager Natalee Holloway, wants to be temporarily transferred to the United States, his attorney Maximo Altez said Tuesday.

Van der Sloot is set to be extradited from Peru to the United States to face extortion and fraud charges related to an alleged plot to extort Holloway's family after her disappearance, Peruvian officials have said.

Altez said he received a letter from van der Sloot last week asking the attorney not to appeal his transfer to the United States. "I want to go to the US," van der Sloot wrote, Altez told CNN en Español on Tuesday.

Van der Sloot was involved in a fight inside his prison ward during visiting hours on Saturday and suffered a cut to his fingers and some bruising, Altez said. He was placed in the prison's medical section, Altez said.

"It wasn't a direct assault against him, it was a fight among some inmates and my client got involved when he tried to defend his friend, who was injured on the leg. As a consequence (Joran) got injured in his hand," Altez told CNN en Español.

The attorney had earlier said his client had been "severely" beaten, ABC News reported.

Van der Sloot, a Dutch national, was convicted in 2012 of murdering Stephany Flores, 21, in his Lima hotel room and sentenced to 28 years in prison.

"He (van der Sloot) was not beaten. He was not attacked," a spokesperson for the Peruvian National Penitentiary Institute said in a statement sent to CNN en Español on Monday.

The spokesperson did not comment further.

Altez told CNN en Español that van der Sloot sent him another letter the day after the incident requesting his transfer to another ward or another prison.

Altez can't communicate directly with his client as there are no phones inside Peru's Challapalca Prison, so they communicate by letter, he said.

An attorney for the Holloway family, John Kelly, declined to comment when reached by CNN Tuesday.

Van der Sloot faces extortion and fraud charges in connection with an alleged plot to sell false information about the whereabouts of 18-year-old Holloway's remains in exchange for $250,000. Holloway's mother, Beth Holloway, wired $15,000 to a bank account van der Sloot held in the Netherlands and through her attorney gave him another $10,000 in person, according to a 2010 US federal indictment.

Once he had the initial $25,000, van der Sloot said he would show the attorney, Kelly, where Natalee Holloway's remains were hidden, but the information turned out to be false, the indictment states.

The indictment asks for van der Sloot to forfeit $25,100. That amount includes $100 Beth Holloway initially transferred to van der Sloot to confirm his account.

Natalee Holloway was last seen alive with van der Sloot and two other men 18 years ago leaving a nightclub in Aruba.

Police in Aruba arrested and released the three men -- van der Sloot and brothers Deepak and Satish Kalpoe -- multiple times in 2005 and 2007 in connection with Holloway's disappearance. Attorneys for the men maintained the men's innocence throughout the investigation.

In December 2007, the Aruban Public Prosecutor's Office said none of the three would be charged and dropped the cases against them citing insufficient evidence.

Holloway's body has not been found. An Alabama judge signed an order in 2012 declaring her legally dead. No one is currently charged for her death.