(Reuters) - Thousands of people in central Vietnam demonstrated peacefully on Sunday against government plans to lease new economic zones to foreign investors, witnesses told Reuters, a few days after protesters in a nearby province clashed with police.

Protesters fear the leases may be snapped up by investors from powerful neighbor China, with which Vietnam has a rocky history, and were also upset about a recently-passed cybersecurity law that they worry would limit free speech.

Public protests in Vietnam are usually quickly quelled by the police. The ruling Communist Party, despite sweeping economic reform and increasing openness to social change, retains tight media censorship and tolerates little criticism.

Security on Sunday was tight in many cities and provinces in Vietnam, with large presence of police in public areas.

But in central Ha Tinh province, thousands of people attending a Sunday mass protested peacefully against the laws, three witnesses told Reuters, confirming livestream footages on Facebook.

Protesters held signs that said “No leasing land to Chinese communists for even one day” or “Cybersecurity law kills freedom”. The protest in Ha Tinh province lasted for two hours on Sunday morning without clash with the police, witnesses said.

Earlier this week the Vietnamese government vowed to punish “extremists” it said had instigated rare clashes with police where protesters hurling bricks and Molotov cocktails at police and damaging some government buildings in Binh Thuan province.

Vietnam’s National Assembly chairwoman on Friday said the lawmakers condemned “the acts of abusing democracy, distorting the truth, provoking, causing social disorder and greatly affecting the people’s life,” she said in a televised session.

General Secretary Nguyen Phu Trong in a talk with Hanoi citizens on Sunday called for the people to be calm and trust the Communist party and the government, state-run radio news website Voice of Vietnam reported.

“(We) do this for the nation, for the people and no other purpose and no one is that foolish to hand over land to foreigners for them to come and mess things up,” Trong was quoted as saying.