The NGOs from Khasi-Jaintia and Garo hills threatned to launch "intensive agitational programmes" to pressurise the government.
Members from different organisations attended a public rally where the Khasi Students Union (KSU) president Daniel Khyriem threatened agitation if there was no outcome of the meeting convened by the government on August 29 to discuss the issue.
The government should immediately consider the recommendation of high level committee on influx headed by then Deputy Chief Minister Bindo M Lanong for implementation of ILP, Khyriem said.
In view of the public meeting, police tightened security while shops and business establishments remained closed.