NEW DELHI: Railways has suspended all passenger train services in Tripura and Assam and short-terminated long distance trains to the region to Guwahati following protests in the two states over the passage of the Citizenship Amendment Bill in Parliament, a railway spokesperson told PTI on Thursday. Several airlines in the country have also announced that flights to Guwahati and Dibrugarh have been cancelled on Thursday and Friday, and passengers travelling to these two cities will be offered a fee waiver on cancellation or rescheduling fee.The decision was taken Thursday night in view of the security situation in the region, Northeast Frontier Railway spokesperson Subhanan Chanda said, adding many passengers are stranded in Kamakhya and Guwahati.An official at Kolkata's Netaji Subhas Chandra Bose International Airport said that all flights between Kolkata to Dibrugarh sector have been cancelled due to the current situation in Assam.IndiGo announced that all its flights to and from Dibrugarh in Assam are cancelled for Thursday due to unrest in the state."Due to the prevailing situation in Assam, flights to/from Dibrugarh are cancelled for today. Flyers can choose an alternate flight or get a refund," IndiGo said.Other airlines like Vistara and GoAir also announced the cancellation of flights to these two cities and waiving of cancellation or rescheduling fee."Due to the ongoing unrest in Assam, we are waiving rescheduling/cancellation fee to the customers travelling to and from Guwahati and Dibrugarh till Dec 13, 2019. Fare difference if any, will be applicable. Thank you," Vistara tweeted.