BJP Delhi unit President Manoj Tiwari has sought an upgrade in his security cover from 'Y' to 'Z' category from the Centre in the wake of what he called the "recent attacks" on him in West Bengal and the national capital.In a letter to Union Home Minister Rajnath Singh on Monday, Tiwari said: "Two recent attacks on me -- one in West Bengal after the state government's refusal to provide security during campaigning and another at Delhi Chief Minister Arvind Kejriwal residence -- prove that the 'Y' category security given to me is not adequate."Tiwari, the Bharatiya Janata Party (BJP) MP from northeast Delhi, was referring to an alleged attack on a delegation of BJP leaders on January 30 by Aam Aadmi Party legislators and anti-social elements at Kejriwal's residence when they had gone there for a discussion to find a way to provide relief to traders affected by the ongoing sealing drive."Thus, I request you to upgrade my security cover to 'Z' category," Tiwari said.He said he visits other states as part of the party's campaigning and expansion programme.The 'Z' category security entails 20-25 commandos for a protectee.The cover also extends to the residence of the protectee, who is also provided pilot and escort vehicles.