The Bureau of Immigration (BI) was prodded Thursday to intensify its investigation into allegations that some Chinese nationals, including those listed as students in Cagayan schools, were spies or members of sleeper cells.

Sleeper cells are groups of partisans or combatants injected into a target country who conduct normal or mundane lives until they are called upon by their principal country to spring into action at an opportune moment.

Concerns over potential espionage were raised after an inordinate number of Chinese students had enrolled in the country, particularly in Cagayan province where Philippine military bases hosting American troops and ordnance are located. This amid China’s heightened aggression in the West Philippine Sea.

But unless proven otherwise, Sen. Francis Escudero emphasized, the accusations against the Chinese nationals “remain baseless, unfair and should not cause undue alarm.”

“For now, we have nothing to worry about unless there’s enough evidence projected,” said Escudero in Filipino in a television interview.

The senator, however, stressed the BI should be questioned for allowing a “growing number of Chinese students” into the country.

“If there is doubt that they are spies, why didn’t the Bureau of Immigration do its job,” he asked.

He noted that only the BI could shed light on the matter and ascertain whether any lapses had been committed in carrying out its responsibilities.

Meanwhile, Senator Win Gatchalian filed a resolution calling for an inquiry into the foreign students’ supposed payment of up to P2 million to acquire degrees from various private institutions in Cagayan.

The security concerns over the influx of Chinese students in the province were raised after Dr. Chester Cabalza, a University of the Philippines professor and founding president of the think tank International Development and Security Cooperation, reported their alleged payments for college degrees.

Gatchalian urged the Commission on Higher Education (CHEd) to look into Cabalza’s report.

The CHEd earlier tagged Cabalza’s allegations as serious, saying it would investigate after Cabalza filed a formal complaint with the necessary evidence.