NEW DELHI — An alliance of India’s opposition parties launched its election campaign with a massive rally Sunday that criticized Prime Minister Narendra Modi’s government of stifling opponents and undermining democracy ahead of a national election next month.

The “Save Democracy” rally in New Delhi was the first major show of strength by the opposition bloc INDIA. Modi on Sunday also launched a formal campaign for the election to be held over six weeks starting April 19.

Opposition leaders spoke to the flag-waving crowd and criticized Modi’s government for arresting several of their colleagues, including New Delhi’s top elected official Arvind Kejriwal on March 21. The leaders called the arrests undemocratic and accused Modi’s Bharatiya Janata Party, or BJP, of using federal agencies to undermine the opposition.

Kejriwal was arrested by the federal Enforcement Directorate on charges that his party and state ministers had accepted 1 billion rupees ($12 million) in bribes from liquor contractors nearly two years ago. The Aam Aadmi Party, or Common Man’s Party, denied the accusations and said that Kejriwal would remain as New Delhi’s chief minister while the court decides on the next step.

In January, the agency arrested Hemant Soren — until then the chief minister of eastern Jharkhand state — for allegedly facilitating an illegal land sale. Soren’s party denies the charges.

“This battle is to safeguard the nation, democracy, constitution, future of the nation, youth, farmers and women. This battle is for justice and truth,” Deepender Singh Hooda, a lawmaker of the opposition Congress party, told reporters at the rally.

Kejriwal’s arrest is seen as a setback for the opposition bloc that is the main challenger of the BJP in the elections.

The BJP denies targeting the opposition and says law enforcement agencies act independently.

“Narendra Modi wants to strangle democracy and take away the option from the people to choose the government of their choice,” opposition leader Rahul Gandhi from the Congress party, who took part in Sunday’s rally, wrote on X.

Modi kicked off his campaign for a third term from the city of Meerut, some 100 kilometers (60 miles) north of New Delhi.

Modi said the opposition was uneasy because of the administration’s crackdown on corruption. “While Modi’s mantra is to eradicate corruption, their (opposition parties) credo is protect the corrupt,” he said.