In a letter written to Home Secretary Madhukar Gupta, the ministry, expressing deep concern over the issue has sought ‘immediate action to organise adequate security measures to protect the lives of the staff working on the project in the North-East’.

The incidents have created a sense of fear among the railway employees engaged in laying tracks and other projects in the region, a senior railway ministry official said.

The ministry has also been prompted into action as the railway works have been hit majorly by the attacks.

The work has come to a standstill at all the sites due to these incidents, he said, adding, "That is why we are seeking the Home Ministry's intervention for protection of workers in these sites to ensure continuation of the work."

Two workers were killed and another injured when the militants opened fire on a labour camp site near Migrandisa railway station in Assam on Monday.

The attack came a day after eight workers, employed by a contractor in the Lumding project in Assam were killed by militants on Sunday.

On Saturday last, militants opened fire randomly in Wadrengdisa, also in Assam, killing a railway staff and two civilians.

Earlier, a railway engineer involved in Kumarghat-Agartala new line project in Tripura was kidnapped and a contractor's staff was killed by militants on April 26.