BRAZZAVILLE, Republic of Congo (AP) — Police in Republic of Congo's capital fired tear gas Tuesday to try to disperse protests against a constitutional referendum to make the country's longtime president eligible for a new term, say residents.

Politicians campaigning against the Oct. 25 referendum called for a campaign of "civil disobedience" to begin Tuesday.

"This morning, young people went onto the streets to burn tires and erect barricades," said Rudel Ganziami, a resident of Brazzaville's southern Bacongo district. "Right now the police are firing tear gas grenades to try to disperse them."

Phone and internet service appeared to be down in much the city on Tuesday.

Under current laws 71-year-old President Denis Sassou N'Guesso is barred from seeking re-election when his second term expires next year. The referendum calls for the limit of two terms to be scrapped as well as changing a regulation preventing candidates older than 70 years.

The protests in Brazzaville come after six people were injured in weekend clashes in Repbublic of Congo's second largest city, Point-Noire.

Prosecutor Andre Galaka Oko issued a statement Saturday warning of "very heavy penalties" for those who threaten public order. In Brazzaville, families have been stocking up on food and expressing concern about violence in the coming days.

By the time his current term ends next year, Sassou N'Guesso will have served more than 30 years as leader of this Central African nation, though not continuously.

He first ruled the country of more than 4 million people from 1979 until a 1992 election defeat. He then seized power in 1997, following a civil war in which his rebel forces ousted the president. He was elected in 2002 and then again in 2009 for what was to be his second and final seven-year term.