The boat was carrying 16 tourists and three crew members.

At least four people are dead after a boat carrying over a dozen tourists sank in the waters off the coast of Cancun.

The boat, which was traveling from Isla Mujeres to Puerto Juárez, caught a strong sea swell and the vessel began to sink as it took on water, ABC News has learned from officials close to the investigation.

The boat was carrying 16 tourists and three crew members at the time of the accident, authorities said.

At least four people have been confirmed dead — two adult males, one adult female and one minor — while seven people are still missing. Authorities have not yet released any of the passenger’s identities while the rescue operation is still underway.

Eight people have been rescued so far but their conditions, as well as the nationalities of the passengers involved, are currently unknown.

This is a developing story. Please check back for updates.

ABC News’ Anne Laurent contributed to this report.