Pune, May 22 : The Maharashtra Navnirman Sena President Raj Thackeray has said he would undergo a surgery for knee and back problems on June 1, but the party's 'anti-loudspeakers' agitation will continue, here on Sunday. "I shall be undergoing hip bone surgery on June 1... I have been in pain since some time in the legs and now also in the back," Raj -- the estranged cousin of Chief Minister Uddhav Thackeray -- said at a rally here. Post-surgery, he would be recuperating for a couple of months but promised to write a letter to 'all Hindu sisters and brothers' on the MNS' ongoing agitation against loudspeakers on mosques in the state. "For the first time in Maharashtra's history, the early morning 'azans' have stopped being played on loudspeakers... It was due to the MNS... If they increase their volume, then our campaign will be started again. Our Hindutva gives results," claimed Raj. He also took a swipe at the Rana couple -- independent MP Navneet Kaur-Rana and her MLA husband Ravi Rana -- for their 'Hanuman Chalisa' agitation plans outside the CM's private residence 'Matoshri'. "What I had said was Hanuman Chalisa would be played outside mosques blaring out 'azan' on loudspeakers. What was the need for the Rana couple to go to 'Matoshri' - is it some kind of mosque? Then all the controversy, their arrests, jail, release, and statements started," he said. Raj also took the opportunity to justify his 2008 agitation against the north Indian communities, reiterating that they were depriving Marathi local youths of jobs in railways, and blamed the north Indians for triggering the violent reaction by MNS activists then. It may be recalled that the MNS chief was planning to go on trip to Ayodhya on June 5, but last week he abruptly cancelled it, and was interpreted as a huge setback to the party. There was much speculation whether the trip was deferred owing to certain health issues and he himself set right the records Sunday. Earlier, he faced jibes from many politicians, including from the ruling Shiv Sena- Nationalist Congress Party-Congress, and other parties over the Ayodhya tour cancellation, especially since it came at the peak of the 'anti-loudspeakers' row in the state. The trip postponement was sought to be linked with threats by an Uttar Pradesh Bharatiya Janata Party MP Brijbhushan Sharan Singh who has openly "vowed" to block Raj's entry there till he apologises for the humiliating treatment meted out to North Indians during the MNS's 2008 agitation. /IANS