United Nations (CNN) -- A protest Friday afternoon outside Iran's U.N. mission in New York kicks off a weekend of events demanding the country release three American hikers it has held for one year.
"Free the Hikers," an organization formed by their families, will stage a protest at the Iranian mission to the United Nations on Friday afternoon. More protests are planned through the weekend in cities around the world, according to the group.
"The event is going to kick off a weekend of action. We have events in cities from India to Spain and all throughout the U.S. It's really a global issue," Alex Fattal, older brother of Josh Fattal, told CNN. "We want to send Iran a message."
The hikers -- Josh Fattal, Sarah Shourd, and Shane Bauer -- are still being held in Tehran, a year after their July 31, 2009, arrests.
The three Americans were detained after they allegedly strayed across an unmarked border into Iran while hiking in Iraq's Kurdistan region. However, The Nation magazine reported last month that two witnesses have said they saw members of Iran's national police force cross into Iraq to apprehend the three.
Tehran has claimed the three hikers are spies. Iran's intelligence minister has hinted the country may consider releasing them in exchange for the release of Iranian prisoners, according to state media.
Family members, who say the three were enjoying a recreational hike when they were detained, say they still have not been informed of the reasons behind their imprisonment.
"Iranian law says that if you've spent the minimum time in jail without seeing a judge you must be released. So we hope Iran will honor its own laws," Alex Fattal said.
The mothers of the three hikers met with their loved ones in May in Iran in emotional sessions. Iran later cut short the visas issued to the parents.
"For 23 hours a day, Sarah sits in a cell by herself, for absolutely no reason," Alex Fattal said. "Sarah has a pre-cancerous condition that needs continual monitoring. Health records have not been made available to her family."
U.S. Secretary of State Hillary Clinton has asked the hikers be released and "allowed to return to their families on a humanitarian basis."
"Iran is using my brother and his friends in some sort of cynical ploy to exert leverage. They should not be caught up in the political tensions between Iran and the U.S.," Alex Fattal said.
The hikers could not have strayed at a more unfortunate time; six weeks earlier there were violent anti-government protests on the streets in Tehran, and the United States was in the midst of fighting Iran's nuclear-fuel enrichment program.
A year later, prominent figures are still speaking out in their defense .
"There are numerous influential individuals and other governments who have raised the case," Alex Fattal said.
According to Alex Fattal, they include retired South African Archbishop Desmond Tutu; Ila Gandhi, Mahatma Gandhi's granddaughter; Nobel Peace Prize winner Mairead Maguire; and Fernando Henrique Cardoso, former president of Brazil.