A group of NCP activists today barged into the Aam Aadmi Party office in suburban Andheri, tore and burnt posters of Arvind Kejriwal and also burnt his effigy, police said.The attack comes two days after AAP leader Anjali Damania targeted senior NCP leader and Maharashtra Deputy Chief Minister Ajit Pawar, saying that Mumbai citizens were paying high electricity charges due to corruption and inefficiency of the state power ministry.23 activists were later arrested in connection with the incident."We have arrested 23 activists of Nationalist Congress Party (NCP) for rioting, mischief and trespassing among other charges under the Indian Penal Code," said Milind Bharambe, Additional Commissioner of Police.Police also detained AAP leader Mayank Gandhi when he was heading for the NCP office in suburban Juhu to protest against the attack."Gandhi has been detained. He will be allowed to go later in the evening," said Bharambe.According to the police, 20-25 activists of NCP, led by Prithiviraj Maske (north-west district NCP president), and Amol Matele (president of NCP students wing), entered the second floor of AAP office at Chakala and tore up and burnt the posters of around 2.30 PM. They also burnt Kejriwal's effigy.Immediately after the attack the AAP tweeted, "AAP Maharashtra office attacked by NCP goons".AAP volunteer Paritosh said the attackers threw bottles of black ink and damaged party banners. He also accused that the attackers used obscene words and shouted slogans."Police had to intervene and take them away," he said, adding that AAP will submit CCTV footage at the office to the police.

Meanwhile, NCP spokesperson Nawab Malik said that the party had expelled Matele over the incident. "The party does not endorse this act," Malik said.