Agents with U.S. Customs and Border Protection have arrested two Chinese nationals suspected of using an ultralight aircraft to illegally cross the southern border.

At around 1.45am on Tuesday, Border Patrol agents detected the aircraft entering U.S. airspace in Southern California's Imperial Valley, across the border from Mexicali.

Running without lights, the ultralight traveled well into the U.S., landing near Calipatria some 30 miles from the nearest border crossing, CBP said in a statement.

Agents tracked the craft to its landing site, but the fixed-wing ultralight took off on a return course for Mexico before it could be seized.

The US border is seen from the Mexican side in the El Centro sector, where an ultralight smuggled two Chinese nationals into the U.S. on Tuesday. White vehicle barriers are seen

In the vicinity, Border Patrol agents found two Chinese nationals who they suspect entered the country illegally on the ultralight craft. The two men were ages 30 and 23, CBP told DailyMail.com.

Agents also discovered a 36-year-old Mexican national in a waiting vehicle whom they suspected was part of the human smuggling scheme.

The Mexican national was found to be legally present in the U.S. in possession of a border crossing card.

All three were arrested and transported to Calixico Station for processing.

It was the second time in as many days that CBP tracked an ultralight craft in an illegal crossing on that stretch of the border.

On Sunday at about 12.10am, agents tracked an ultralight with no lights crossing the border into the U.S. near Calexico.

The aircraft swooped over the border, descended to a low altitude, and then gained altitude and flew back into Mexico.

Agents responded to the location and discovered two brown zippered bags lying under heavy brush, a metallic cage and a bicycle in the agricultural field where the aircraft was observed to have dropped in altitude.

On Sunday, CBP seized 60 duck taped bundles of meth (above), a metallic cage and a bicycle in the field where an ultralight aircraft was observed to have dropped in altitude

Border Patrol also spotted two individuals in the vicinity who were interviewed and arrested on suspicion they were receiving the dropped narcotics.

At the station, agents unpacked 60 duck taped bundles containing white powder-like substance inside of the two zippered bags that tested positive for the characteristics of methamphetamine. The combined weight of the packages totaled 129.33 lbs., with an estimated value of $1,422,553.

'Ultralight aircraft not only pose a threat to legitimate air traffic in the vicinity, but also to national security,' said Chief Patrol Agent Gloria I. Chavez in a statement.

'These aircraft are able to carry small payloads of dangerous cargo or dangerous people.'