Authorities in Tijuana, Mexico, are searching for a 2-year-old boy who reportedly fell through an open manhole into a sewer over the weekend.

U-T San Diego (http://bit.ly/16jpGyQ ) says scores of rescue workers scoured underground tunnels and pipelines and used cameras Tuesday to scan dozens of sewer openings. The paper says authorities are exploring 20 miles of pipelines near the U.S.-Mexico border.

His parents say Ivan Sanchez fell into a sewer on Sunday morning as the family walked to a park.

Authorities say he would have fallen nearly 10 feet, and lack of oxygen in the pipes would make survival difficult.

However, they are continuing the search.