An FIR was filed against Assam Chief Minister Himanta Biswa Sarma and other top officials of the state, including 'attempt to murder', at a Mizoram police station after an escalating border dispute between the two states. Expressing his willingness to join the probe, Mr Sarma tweeted: "Will be very happy to join in any investigation. But why the case is not being handed over to a neutral agency...". The two states have been at odds over the border for decades and the situation flared up this week. On Monday, violence broke out at the border area with each side accusing the other of starting the violence.