American hikers Shane Bauer (L) and Josh Fattal (C) and their translator attend the first session of their trial at the revolutionary court in Tehran February 6, 2011. [Photo/Agencies]

TEHRAN - The lawyer of the three US nationals detained in Iran on charges of espionage two years ago expressed hope that they would soon be released, the local satellite Press TV reported on Sunday.

The fourth and the last trial session to address the charges against Josh Fattal, Sarah Shourd and Shane Bauer was held Sunday in the Branch 15 of Tehran's Revolution Court, said the report.

Talking to Press TV in a telephone interview on Sunday, the lawyer, Masoud Shafiee, said he hoped they would be sentenced to time served.

"According to the law, the court is obligated to issue the verdict within one week," Shafiee was quoted as saying.

Josh Fattal, Sarah Shourd and Shane Bauer were arrested in Iran on July 31, 2009 for illegally entering Iran's western border and were later charged with espionage. The US government considered the charges totally unfounded.

The female US hiker Sarah Shourd, once jailed in Iran with the other two Americans, was released by Tehran's prosecutor in September on bail of $500,000 due to her health situation.