Three people have reportedly been arrested as a desperate search is stepped up for two Australian brothers and their travel mate who have mysteriously disappeared in Mexico.

Brothers Jake and Callum Robinson, aged in their 30s, vanished on a surfing and camping trip in Baja California state five days ago and haven’t been in contact with family and friends.

Mexican police searching for the pair in the coastal cliff region of La Bocana on Thursday (AEST) were alerted to one of their phones being switched on, local media report.

The phone reportedly pinged a mobile phone tower, which enabled authorities to pinpoint the location to about an hour’s drive from where the Robinson brothers were last seen near the city of Ensenada.

Police tracked the phone to a local woman, aged about 25. She was arrested, according to Mexican journalist Mario Munoz.

Munoz told the ABC the woman was also in possession of a quantity of drugs.

Then in an update on Friday morning (AEST), local authorities confirmed another two people had been arrested, and abandoned tents had been discovered, according to the Nine Network.

The region is known to be in the grip of a turf war between rival drug cartels.

A search is underway in the La Bocana coastal cliff region. Photo: Wikiphotos

A search group called Colectivo Una Nación Buscando (Collective One Nation Searching) said there were almost 18,000 missing people in Baja California. That was up about 4000 on two years ago.

The Robinson brothers were travelling with American tourist Jack Carter Rhoad, who is also reported as missing.

The brothers failed to check in to their Airbnb accommodation after their surf trip and Callum was said to be due back to work in San Diego where he lives, but never turned up.

There are growing fears for the brothers, and their mother Debra Robinson has appealed for help.

She has posted alerts on various social media platforms in Mexico, outlining the family’s concerns and pleading for information.

Brothers Jake and Callum Robinson are missing in Mexico, along with their friend Jack Carter.

“Reaching out to anyone who has seen my two sons,” she wrote on a Talk Baja Facebook group.

“They have not contacted us since Saturday 27th April. They are travelling with another friend an American citizen.

“They were due to book into an Airbnb in Rosarito after their camping weekend but they did not show up.

“Callum is a type one diabetic so there is also a medical concern.

“Please contact me if you have seen them or know their whereabouts.”

Baja California state in Mexico, near the US border. Photo: Wikipedia

The Baja California attorney-general’s office is in charge of missing persons in the state.

Lawyer María Elena Andrade Ramírez was appointed to the role in August 2023 and promised to focus more on missing people by creating a special prosecutor’s office and investigation unit.

She was due to address the media about the missing brothers on Friday.

The Department of Foreign Affairs and Trade has confirmed it is helping the family.

“Owing to our privacy obligations we are unable to provide further comment,” a spokesperson said.

In 2015, WA surfers Adam Coleman and Dean Lucas were murdered, believed to have been shot by gang members in Mexico’s volatile Sinaloa region, before their van and bodies were burnt.