MANILA, March 1 -- The Bureau of Immigration (BI) on Saturday reported the arrest of five Chinese nationals involved in illegal mining in Isabela province.

Xue Xianrong, Xingyue Qiu, Zeng Shuiying, Zhang Huaping and Xue Junfeng were apprehended on Feb. 27 while working at a mining site in Barangay Caguilingan, Cordon, according to a news release.

The operation was carried out by the BI Regional Intelligence Operating Unit II, which found that the five were working without necessary permits or visas.

Upon inspection, the foreign nationals failed to present valid immigration documentation, aside from digital copies of their passports stored on their mobile phones.

Further verification confirmed that they lacked the proper visas required...