Relatives of two Americans accused of spying in Iran are pleading for their humanitarian release to coincide with the holiday marking the Iranian New Year.

The families of Shane Bauer and Josh Fattal said the holiday of Nowruz is a "time for families to come together" and to reflect on the previous year with a look to the future.

"We extend our best wishes to everyone in the Islamic Republic of Iran, in the United States and around the world who celebrates this important occasion and, from the depths of our despair, appeal to the political and religious leaders of Iran to show compassion and make this a time when we, too, can at least be together again as families," a statement released on Tuesday read.

Bauer, Fattal and Sarah Shourd were hiking in northern Iraq near the Iranian border in July 2009 when they were detained by Iranian forces, who accused them of spying for the United States. The Americans and their families have denied those charges.

"Shane and Josh have spent nearly 600 days in detention," the statement continued. "Their mothers have met them just once during these long and painful days and Shane and Josh have had only two brief telephone calls with family members … We implore the Iranian authorities to show compassion and end their isolation from their families and people around the world who love and care for them."

Bauer and Fattal pleaded not guilty to the charges in February. They are due to return to an Iranian court on May 11. Shourd was released on bail in September and has pleaded not guilty in absentia.

While imprisoned in Iran, Bauer proposed to Shourd. Fattal is expected to serve as Bauer's best man once he is released.

"It is time for this to end," the statement concluded. "It is time for a humanitarian spirit to prevail and to begin a new year, filled with happiness and renewed faith in the liberating power of compassion."