Friends and relatives of a boy who disappeared from a Toronto hospital are coordinating their search efforts over the Internet.

Robert Frydman, 15, went missing from the Hospital for Sick Children early Saturday morning.

Since his disappearance, supporters have flooded various social media sites with updates about the boy.

In a message posted to Facebook, Frydman's mother Daniele Gauvin said the boy may be "cold, weak and confused" after his stay at the hospital where he was being treated for dehydration.

More than 200 people have joined a Facebook group dedicated to finding the boy. Supporters are also spreading a description of the boy via Twitter messages, and there is a missing persons posting for him on the classified ad website Kijiji.

"We urge everyone to keep up their efforts for his safe return… It's been 30 hours now and time is pressing," the boy's parents wrote in a news release issued Sunday afternoon.

A man who identified himself as Frydman's uncle posted the press release to his Twitter account under the label "#AmberAlert." Ontario Provincial Police, however, haven't issued a formal Amber Alert.

The OPP warning is issued when a child has been abducted and is considered to be in imminent danger.

Father says boy placed call to Calgary

Police sent officers to a food court in Toronto's financial district on Sunday evening, after the boy's father told police the 15-year-old had placed a call from the area.

Officials said the boy's father Barry Frydman called police at about 6:30 p.m., telling them his son called a friend in Calgary from the First Canadian Place complex on King Street West.

Further details about the phone call were not immediately available.

Police said they could not find the teen when they arrived at the food court.

Toronto police said Sunday that the search for Frydman remains at a "level two" status. Level three is the most serious search status.

Police added there is no indication that the boy will harm himself.

Frydman's parents said they are worried for their son's health and safety.

"We are very worried that he may have spent the last two cold rainy nights curled up in an alley for warmth somewhere, or that he's somewhere warm but not safe for him," the boy's parents wrote in a release.

Frydman is described as white, 5-foot-6, 125 lbs, with short brown hair and dark eyes.

He was last seen wearing a light grey sweater and light grey sweat pants. He was wearing black socks and no shoes.

Anyone with information about the teen is encouraged to contact Toronto police at 416-808-5200.