MOSCOW, September 17 (RIA Novosti) - A U.S. district court sentenced on Wednesday wealthy businessman and charity founder Andrew Mogilyansky to eight years in prison for having sex with teenage girls, the Philadelphia Inquirer said.

Indicted in December, Mogilyansky, a dual Russian-U.S. citizen, pleaded guilty to the charges in April. The prosecution said he took two thirteen-year-old girls and one fourteen-year-old to his apartment in St. Petersburg from their orphanage where he had sex with them.

The judge also ordered Mogilyansky to spend 15 years on supervised release after serving his prison term, and to pay $5,000 in compensation to each of his victims, and a $12,500 fine, the paper said.

"This is a grave criminal act," said Judge Mary A. McLaughlin. "Their [the victims] lives will be different because they were harmed by Mr. Mogilyansky."

Mogilyansky was initially charged with organizing an online child prostitution ring in the Russian capital and bringing over orphaned girls from St. Petersburg from 2002 to 2004 together with four other men, who were tried and convicted in Russia in 2004. He faced 15-30 years in jail.

The charges were later dropped for those of "sex tourism." The prison term is at the top of the sentencing-guideline range for the crimes.

Going abroad to have sex with underage children is known as sex tourism. It falls under a federal law that allows U.S. authorities to prosecute Americans who have sex with children on foreign soil.

That office began looking at Mogilyansky in 2004 after Russian authorities identified him as a suspect in their investigation of an Internet-based prostitution business.

The courtroom was filled with Mogilyansky's supporters. His wealth was reported at about $5 million from his businesses, including a car export firm and publishing the Russian Yellow Pages, the paper said.