NAKHON SI THAMMARAT, Thailand (AP) — At least 30 police officers in southern Thailand were injured Monday in a new round of clashes with demonstrators protesting what they considered to be an inadequate government offer to help rubber farmers, authorities said.

The protesters clashed with police as they attempted to reclaim a traffic intersection they previously blocked in Cha-uat district in Nakhon Si Thammarat province, 580 kilometers (360 miles) south of Bangkok, said Police Maj. Gen. Somchai Uamthanom. Hundreds of anti-riot police had cleared protesters from the intersection earlier in the day.

Somchai said protesters, mostly teenagers, hurled rocks, bricks and bags of acidic liquid at officers who responded with tear gas.

Several police vehicles were damaged and set on fire, while a few gunshots were heard during the clash. Somchai said police retreated.

An unknown number of protesters also were hurt.

Tension was renewed over the weekend in southern provinces after farmers declined the government's offer to subsidize rubber prices.

Last week, the Cabinet approved a 21.2 billion baht ($657 million) program for the farmers but it was never formally accepted by some farmers' representatives who threatened to take a more hard-line stand in their demands, include shutting down a port, a border checkpoint and a major road junction in the south, where most of the country's rubber is grown.

The disruptive but generally peaceful protests turned violent two weeks ago, in one case leaving more than 20 police officers injured after bricks and bottles were hurled at them.

Thailand is the world's top producer and exporter of natural rubber, which is used in products from condoms to car tires. Due to weaker demand in a sluggish global economy, prices for rubber have steadily dropped since peaking in 2011.