At least 12 lakh Bangladeshis, who have entered India between 1972 and 2005 with valid documents, have not returned home, Director General of BSF A K Mitra said on Monday.

''Between 1972 and 2005, 12 lakh Bangladeshi have entered West Bengal with valid documents. But there is no record that they have returned home," Mitra told reporters.      His comments came when asked whether the issue of illegal immigrants had figured in the five-day DG-level talks between BSF and BDR which ended in Dhaka today.

"Illegal immigrants is no longer a serious problem. The number of illegal immigrants entering India has been reduced considerably," he said.

Mitra said last year only 807 illegal immigrants were arrested along the Indo-Bangla border in comparison to five years ago when thousands of such persons were apprehended by the BSF.

Asked about the reports of demographic change in certain border areas due to the influx, the BSF chief said, "The problem is there. Various government agencies are working.

Even special laws like IMDT (now defunct) were framed to deal with the illegal immigrants".