FERGUSON, United States, Aug. 18 -- Missouri Governor Jay Nixon signed an order on Monday authorizing use of the National Guard in the riot-hit U.S. town of Ferguson, after violent clashes between protesters and the police.

"Given these deliberate, coordinated and intensifying violent attacks on lives and property in Ferguson, I am directing the highly capable men and women of the Missouri National Guard ... in restoring peace and order to this community," Nixon said in a statement.

Unrest and violence have gripped the area for days since the fatal shooting of black teenager Michael Brown by a white police officer, Darren Wilson.

Fresh violence erupted late Sunday, in which protesters fired upon law enforcement officers, throwing Molotov cocktails, looting and blocking roads.

And the tension further escalated after private autopsy results showed Brown, 18, was shot at least six times, two of those in the head.

"Based on the conditions, I had no alternative but to elevate the level of response," said Missouri State Highway Patrol Captain Ron Johnson.

Monday marks the ninth day of protests in Ferguson after the shooting. Nixon declared a state of emergency in Ferguson on Saturday after the protests turned violent the night before.