Kolkata, Dec. 30 -- : Just before the assembly election in the state, union Home Minister Amit Shah mounted a sharp attack on the West Bengal government on Tuesday, accusing the ruling Trinamool Congress (TMC) of encouraging illegal infiltration from Bangladesh for political gains and warned that the issue poses a serious threat not only to the state but to national security.

Addressing reporters, Shah claimed infiltration in West Bengal had reached alarming levels.

"We will stop infiltration in Bengal in such a manner that not even a bird will be able to enter the country unnoticed," he said.

Referring to reports of illegal entrants settling in border villages, he asked, "Why are Bangladeshis moving freely in villages? Why is the police...