The police on Friday arrested four factory workers who allegedly vandalised a phone manufacturing facility in Uttar Pradesh’s Noida the day before, PTI reported.

“Four workers have been arrested for the violence, throwing stones and damaging the office,” said Station House Officer Akhilesh Tripathi. “They have also been booked for indecent behaviour and scuffling with police officials and obstructing them in the duty.”

The four were identified as Yogesh Kumar, Akhilesh Kumar, Deepak Pandey and Yogesh Pal. All of them are in their twenties.

Around 1,000 employees of Hipad Technology India Private Limited, which manufactures Oppo and Xiaomi phones, protested outside the plant on Thursday after around 200 of them were asked to go on leave. The police took suo motu cognizance of the protest and arrested the four men even though the factor management did not file a complaint.

Meanwhile, the company’s officials in China have written to the Centre, the Chinese embassy in New Delhi, the police and the administration in Noida, thanking them for “the quick response and effective handling” of the incident.

In a statement, Hipad Technology said it had informed the vendor providing them labourers that the supply of materials had been delayed by 10 days after Diwali because of transportation problems. “To prevent loss of employees in the key positions, Hipad India had arranged for human resources department and the vendor’s company to carry out a joint training,” it added. “We had clearly informed the vendors our plan that we will ask these employees to return to the factory and continue to work in December.”

Officials in labour department had also said on Thursday that the protests occurred because of miscommunication.