Congress president Ajay Kumar Lallu and several workers were detained near the party headquarters here on Tuesday when they tried to protest against the arrest of minority cell chairperson Shahnawaz Alam late on Monday in connection with the violence during the agitation against the Citizenship (Amendment) Act in the Uttar Pradesh capital last year. They were all freed later.

Mr. Alam, 37, along with two-three other Congress members, was picked up after 8 p.m. from an apartment near Kalidas Marg, where Chief Minister Yogi Adityanath resides, according to the CCTV footage shared by the party. The others were later released.

After Mr. Alam was driven away in a jeep by policemen in plain clothes, Mr. Lallu and other leaders entered into a heated debated with the police at the Hazratganj station, seeking to know where he was kept and the charges against him.

The police used batons to disperse the Congress workers who had gathered on the station premises, raising slogans.

Dinesh Singh, DCP, Central, said Mr. Alam was arrested in connection with the FIR lodged at Hazratganj on December 19, 2019. “His name had come up [in the case] earlier. The process of evidence-gathering was under way. And after gathering sufficient evidence, we have arrested him,” he said.

According to the FIR filed on December 19 last year, the accused face such serious charges as rioting, attempt to murder and criminal conspiracy. The police recently filed a chargesheet in the case. However, his name did not figure in the FIR or the chargesheet.

Mr. Lallu criticised the police for the manner in which Mr. Alam was arrested and for baton-charging the party workers. “This is the brave police of Uttar Pradesh. They have forgotten their oath under the pressure of their political masters,” he said.

He said the government was trying to foist false cases on Congress workers.

One Congress worker suffered a hand fracture in the baton charge, while some others were injured, Mr. Lallu said. “The government is rattled, the Chief Minister is acting like a coward,” Mr. Lallu, an MLA from Kushinagar, wrote on Twitter.

The Lucknow police had previously arrested another Congress worker Sadaf Jafar in connection with the violence, but freed her on bail.

Congress general secretary Priyanka Gandhi Vadra said the police action was oppressive and undemocratic. “BJP government can make UP police a tool of oppression to stop other parties from raising their voice, but not our party,” she wrote on Twitter.