NEW YORK, November 22. /TASS/. US President Barack Obama has called on residents of Ferguson, Missouri, to “keep protests peaceful” ahead of a grand jury decision whether to indict a police officer in the fatal shooting of black teenager Michael Brown.

“This is a country that allows everybody to express their views. Allows them to peacefully assemble, to protest actions that they think are unjust. But using any event as an excuse for violence is contrary to rule of law and contrary to who we are,” Obama said in an exclusive ABC News interview taped for Sunday's "This Week" program. 

The grand jury in Missouri is due to determine if police officer Darren Wilson who fatally shot the unarmed teenager on August 9 should be charged. The decision is expected to be announced soon, although no precise date is yet known.

The FBI has sent some 100 agents in anticipation of possible unrest. Earlier this week, Missouri Governor Jay Nixon declared a state of emergency which will allow local authorities to use the National Guard in case of protests.

Many schools in the city and its suburbs have cancelled next week’s classes.