(Reuters) - Bahraini police fired tear gas and sound grenades after hundreds of Shi'ite youths demonstrated on Sunday against the death of a 15-year-old protester a day earlier in the Sunni-ruled Gulf island kingdom, residents and activists said.

Confrontations between security forces and protesters take place almost daily in areas populated by members of the Shi'ite Muslim majority, which led anti-government protests Bahrain crushed last year.

After the funeral, many of the mourners started protesting and the police began using tear gas and sound bombs. It is still going on hours later, a resident told Reuters from the mostly Shi'ite Muslim village of Sitra, south of the capital Manama.

At least one demonstrator was injured after being hit in the head by a tear gas canister, activists said in Twitter messages.

The opposition said earlier that Sayed Hashim Saeed, who died on Saturday, had been hit by a tear gas canister at close range.

But officials said the youth's body had extensive burns which could not have been caused by a tear gas canister.

Preliminary investigations show that the deceased was among those who took part in attacks on security forces by throwing petrol bombs, the state news agency BNA quoted a police official as saying.

A coroner's report said the youth had a neck wound which may have been fatal and that the cause of death would be investigated.

Shi'ite youths chanting slogans against Bahrain's royal family clashed with riot police across the Gulf state on Friday and Saturday. Security forces fired tear gas at them in an attempt to keep them from blocking roads.

Inspired by Arab Spring uprisings in Tunisia and Egypt, thousands of mainly Shi'ite Bahrainis took to the streets in February and March demanding curbs on the power of the Sunni Muslim Al-Khalifa family and an end to perceived discrimination.

The broader pro-democracy movement was suppressed with military backing from Bahrain's Sunni-led Gulf neighbors Saudi Arabia and the United Arab Emirates.

At least 35 people including five members of the security forces were killed in the unrest, according to an inquiry Bahrain commissioned into the protests and their aftermath. The inquiry said it found evidence of systematic abuse and torture.

Bahrain has promised to implement the inquiry's recommendations, which the U.S. Congress has linked to its approval of a $53 million arms sale to Manama. Opposition groups doubt the kingdom's commitment to reform.

On Saturday, the independent daily Al Wasat said on its website that the head of the body implementing the recommendations, Ali al-Salih, had handed in his resignation. There was no official confirmation of the report.

Bahrain is important to Western interests in the Middle East because it hosts the U.S. Fifth Fleet and faces Shi'ite giant Iran on the other side of the Gulf. Iran has denied Bahraini government accusations that it has incited the protests.

(Reporting by Nour Merza and Firouz Sedarat; Editing by Angus MacSwan)