Arvind Kejriwal, a potential prime ministerial candidate and, recently and very briefly, the former chief minister of the state of New Delhi, was reportedly detained on the campaign trail in the western Indian state of Gujarat for allegedly violating campaigning norms, leading to clashes Wednesday among supporters of his Aam Aadmi Party, or AAP, and the Bhartiya Janata Party, or the BJP, which is India's main opposition party.

Police in the state of Gujarat, which is run by BJP, reportedly stopped Kejriwal briefly for travelling in a long motorcade, igniting clashes outside BJP’s headquarters in New Delhi and injuring 28 people. And, in New Delhi, police arrested 14 AAP members for rioting with party workers from the BJP, and cited three prominent politicians from AAP for gathering illegally outside the BJP’s office, according to news reports. Both parties are contesting in the upcoming general elections, which begin April 7, and the police action attracted accusations of favoritism against the local police.

“No arrest of BJP leaders and activists till now by Delhi Police ? Is BJP and Police hand in glove !!!” Ashutosh, one of the AAP leaders cited by the police, posted on social-networking site Twitter on Thursday.

“Why no BJP worker and leader is arrested till now? Why only AAP leaders and volunteers arrested?, Can you believe it Prof Anand Kumar, the most respected professor is arrested and Nalin Kohli (a BJP worker) is roaming free,” he added.

Kejriwal apologized for the behavior of his party workers but defended their actions saying that they were instigated.

"I am sorry for the mistakes committed by the AAP workers. They should not have resorted to violence on my detention," Kejriwal said, according to Press Trust of India, or PTI. 

On Twitter, Kejriwal posted: “I urge all volunteers not to raise their hand n to stay calm n non-violent. U shud be prepared to lay down ur life but never raise hand.”

According to Reuters and the Financial Express, a local newspaper, the clashes between AAP and BJP leaders extended to New Delhi's neighboring state of Uttar Pradesh and Gujarat, where Kejriwal was detained. Gujarat is led by controversial leader Narendra Modi, who is leading the polls in the run-up to nationwide elections and is often cited as a favorite to take over as India's next prime minister.

The police used water cannons to curb the violence in New Delhi and reportedly said that about a dozen pedestrians too were injured. The police reportedly detained 33 people after the clashes and arrested 14 of them late Wednesday. Thirteen AAP activists, 10 BJP supporters, four policemen and a media person were injured in the clashes in New Delhi, according to PTI.

"All those identifiable and present at the protest site have been named in the FIR (First Information Report)," Business Standard, a newspaper, reported citing a senior New Delhi police official.