MANILA - (UPDATED) The leader of transport group Piston was arrested Tuesday for charges in connection to a transport strike earlier this year.

Cops arrested Piston President George San Mateo in front of the Quezon City Hall of Justice, where he was supposed to post bail. He was charged for alleged violation of the Public Service Act for leading a nationwide transport strike last February.

San Mateo, who was accompanied by Representatives Antonio Tino of ACT Teachers, and Ariel Casilao of Anakpawis, insisted his right to post a P4,000 bail but the authorities arrested him anyway and was brought to the Quezon City police station 10.

Bagong Alyansang Makabayan (Bayan) Secretary General Renato Reyes earlier said authorities attempted to serve the arrest warrant at the Kilusang Mayo Uno office Monday night.

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"George was not at the KMU office, and Piston is no longer holding office in the building. The police action was underataken late in the evening and was intended to intimidate protesting groups. We will vigorously protest these attacks and all efforts to stifle legitimate dissent," said Reyes.

San Mateo had cancelled off a two-day transport strike originally scheduled Monday after Senator Grace Poe called for transport groups to air their grievances in a Senate hearing.

In an interview with ANC, Poe said she is "a little bit worried" about the timing of San Mateo's arrest, as she has been arranging a dialogue between the transport group leader and Transportation Secretary Art Tugade.

The senator also questioned the charges against San Mateo, who is also accused of violating an LTFRB memo when he led a transport strike.

"There is a provision that says they cannot violate the franchise given to them by not providing service. On the other hand i don't think Mr. San Mateo holds a franchise," she said.

"Every person or every group also has the right to assemble peacefully," she added.

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The Piston-led No to Jeepney Phase-out Coalition mounted transport strikes several times this year, in protest of the government initiative to phase out old jeepney units.

Atty. Aileen Lizada of the Land Transportation Franchising and Regulatory Board previously said a memo by the agency does not allow franchisees to halt operations to protest any government policy.

The LTFRB board member had warned jeepney drivers and operators of losing their franchises if they joined a transport strike.

Last October, President Rodrigo Duterte gave drivers and operators until January to comply with the government's jeepney modernization program.

-- Report from Joyce Balancio, ABS-CBN News