Tamil Nadu Chief Minister J.Jayalalithaa on Monday expressed serious concern at the mob violence targeting Tamils in Karnataka and urged the neighbouring state's government to provide them with necessary security.In a letter to her Karnataka counterpart Siddaramaiah, she said: "As per the reports received, the violence has escalated and a large number of vehicles, including more than 40 buses, 45 lorries and many other vehicles bearing Tamil Nadu number plates have been burnt and damaged."She said groups of protestors from Karnataka are regularly assembling at borders of two states near Hosur and threaten vehicles and commuters from Tamil Nadu.Jayalalithaa said there has been several instances of mob violence targeting Tamil speaking persons and their property in Karnataka."Hotels and properties belonging to Tamils in Karnataka are being attacked and damaged. This is an alarming situation and is causing considerable anxiety," she said.Referring to Siddaramaiah's letter to her on Monday Jayaalithaa said immediately after the Supreme Court issued the order to release Cauvery water to Tamil Nadu instructions to police were given to ensure maintenance of law and order and adequate protection provided to all Kannada-speaking people and their properties in Tamil Nadu."We have ensured that no major incidents of any kind targeting Kannada speaking people or their properties have occurred," she said.