Group gathers in Washington to mark six years since abduction of US freelance journalist Austin Tice, one of at least 30 others gone missing while covering the conflict.

It is believed that at least 30 abducted journalists are being held in Syria, and among them is American freelance journalist Austin Tice, who was kidnapped six years ago.

His family, friends and colleagues have been gathering in Washington to mark the anniversary of his disappearance.

They are calling for the safe release of Tice and dozens of other reporters who have gone missing while covering the conflict.

Al Jazeera's Mike Hanna reports from Washington.