Police denied Wednesday that two demonstrators were killed in a crackdown on hundreds of Nicaraguan farmers protesting the construction of a $50 billion canal across their land.

An opposition leader and activist had said earlier two protesters were killed at the demonstration against the expropriation of land by Chinese firm Hong Kong Nicaragua Development Investment (HKND) to build a massive canal.

At least 21 people were injured and 33 arrested in violence during a police eviction of protesters, police director Aminta Granera said at a conference.

The injured included 15 officers and six civilians, Granera added, including one officer, Armado Gomez, who was in critical condition after a gunshot wound to the chest.

However, Granera denied any protesters had been killed.

Protest leader Eduardo Montealegre had told AFP he saw the bodies of two people, but police blocked protesters from approaching them.

Montealegre said that the crackdown also left many people injured.

Protests followed the inauguration of the canal on Monday by President Daniel Ortega and Chinese billionaire Wang Jing. Police action against the protesters began on Tuesday and intensified Wednesday.

Wang won a 100-year contract to build the canal in 2013. The environmental, technical and financial studies of the 280-kilometer long (175-mile) route have been kept secret.

The canal is expected to displace around 30,000 people, mainly poor farmers and native people, but could be a major financial boon for the Central American nation.

HKND is expected to employ 50,000 people over five years of construction. The canal route crosses Lake Nicaragua and runs through rainforest and at least 40 villages.