Prince Harry says he felt 'guilty' leaving Afghanistan after being exposed by press

— -- While launching the 500-day countdown to the 2018 Invictus Games in Sydney, Prince Harry said he felt "guilty" when he was evacuated out of Afghanistan in 2008 after an Australian magazine violated a news blackout and revealed his location in the country.

"I could no longer stay with my soldiers as it would have put them at greater risk," said Harry, 32. "It was a decision over which I had no control, but the guilt of having to leave my guys behind was something I felt hard to swallow as anyone who has served would understand."

Harry served two tours of duty in Afghanistan during his time in the British Army.

He said in his Sydney speech he resolved on the flight home from Afghanistan to create an event that would ultimately change his life and create a lasting impact on other veterans and wounded service members and their families.

"In these challenging times, we can all benefit from positive and inspiring stories from which to draw strength," Harry said. "The Invictus Games shows us that it is possible to overcome adversity and that the impossible is possible, if you have the will."

Harry, who was a captain in the British Army, founded the Invictus Games in 2014 to raise awareness for wounded service members.

The Paralympic-style sporting event, which will this fall be held in Toronto, is an annual opportunity for injured military personnel to compete internationally against other soldiers, including some they fought with side by side on the battlefield.

Harry's overseas trip began on a somber note after the terror attack in London Saturday that left eight people dead and dozens injured. Harry opened his remarks in Sydney by discussing the attack.

“Can I start by also sending my thoughts to those affected by Saturday's attack in London Bridge,” Harry said. “Australians form an important and vibrant part of the fabric of life in London and we are reminded of that in good times and bad. Our hearts go out to the victims, their friends and families.”

Harry also noted the role wounded warriors played in helping the survivors of the blast at an Ariana Grande concert in Manchester, England, last month that left 22 people dead.

“This spirit, championed by the games, extends far beyond the competition; when a bomb left a number of people with life-changing injuries in Manchester last month, wounded veterans, including Invictus team members, immediately offered themselves up to provide advice and support to the victims through their recovery process," he said. “The commitment to serve is ingrained in every member of the Armed Forces and is the embodiment of the Invictus spirit.”

Harry began his goodwill tour over the weekend with a stop in Singapore, where he participated in a charity polo match to raise funds for his charity Sentebale.

The charity was formed to honor his late mother, Princess Diana, a pioneer in the fight against AIDs. Harry and his brother, Prince William, have been involved in various activities this spring to commemorate the 20th anniversary of their mother's death in Paris in August 1997.

Harry has made it a point throughout the royal tour to honor the fallen.

“Let peace and harmony prevail in communities all over the world,” Harry said.

In Singapore, Harry joined young Muslim youth who were breaking their Ramadan fast in a bid to show communities of all faiths coming together as one in light of the tragedy.

He also visited a children's home which helps recovering addicts and the homeless.