MANILA (Reuters) - Philippine police opened fire as a protest by thousands of rice farmers who lost their crops turned violent on Friday, killing one and wounding about a dozen, a leader of a farming group said.

About 6,000 farmers blocked a portion of the main highway in North Cotabato province on the southern island of Mindanao, demanding government assistance after drought linked by some to El Nino hit hundreds of thousands of hectares of farmland.

“Loud bursts of gunfire erupted,” Norma Capuyan, leader of a farmers’ group, told reporters. “There was heavy volume of fire. We ran to a church compound and the police surrounded us.”

A farmer died on the spot and about a dozen others were wounded in the legs and shoulders, Capuyan said, adding the police first tried to disperse them with water cannon but started shooting when they held their ground.

North Cotabato Governor Emmylou Mendoza said about 20 police were wounded when the farmers attacked them with sticks and stones. She said the first shot was fired by the protesters.

The police issued a statement saying it was investigating.

“Any violation of national police rules and regulations shall be meted (out) with the appropriate penalty,” national police spokesman Chief Superintendent Wilben Mayor said in a statement.

The protest began on Wednesday when farmers barricaded the highway in Kidapawan, demanding a dialogue with the governor and the release of 15,000 sacks of rice she had promised to them as relief.

The agriculture ministry said more than 300,000 hectares of farmland had been affected by drought, causing loses of about 5.3 billion pesos ($115.09 million) in rice and corn. It said the effects of El Nino were minimal.