Anti-government protesters clashed with Bahraini riot police on Monday after the funeral of a teenager who died last week in police custody, part of worsening violence in the run-up to the anniversary of a failed pro-democracy uprising.

Many residents of Sitra, a town inhabited mainly by members of the Gulf Arab state's Shi'ite Muslim majority, were doused in tear gas as police faced off against youths who blocked roads, set tyres alight and threw petrol bombs.

The clashes followed the funeral of Mohammed Ibrahim Yacoub, a 19-year-old who police said died last week from complications resulting from sickle cell disease.

Protesters say he was beaten up by riot police who stamped on him and beat him with batons after his arrest. They said his body showed bruising, abrasions and a cut.

Bahrain has been in turmoil since protesters inspired by revolts in Tunisia and Egypt took to the streets last year to demand democratic reforms in an island state dominated by the ruling Al Khalifa family.

The Sunni Muslim monarchy imposed martial law and invited Saudi and United Arab Emirates troops to crush the uprising in March. Persistent clashes in Shi'ite villages have become more violent in recent weeks, ahead of the February 14 anniversary of the first protests.

A commission of international rights lawyers charged by King Hamad bin Isa al-Khalifa with investigating the protests and crackdown said 35 people died up to the end of martial law in June.

The opposition say that figure has risen to over 60 with a spate of deaths related to the violence since December.

The signs say that the tyrant's day is approaching, the several thousand mourners chanted at the funeral.

People have decided to step up the use of Molotov cocktails because of the abuse they are suffering, said a 25-year-old law student who gave her name as Umm Zahra.

The government says the protesters are hooligans who are holding up economic recovery in the island state, a banking and tourism centre whose economy has slowed down.

The interior minister proposed legislation this week that would increase the punishment for attacking police to a maximum of 15 years in jail.

The government has introduced constitutional reforms giving the elected parliament more powers of scrutiny over the cabinet, but the opposition says it wants the power to form governments.

Bahrain is a key ally of the United States in its face-off with Iran over its nuclear energy programme, and the U.S. Fifth Fleet is based in Bahrain.

(Writing by Andrew Hammond; Editing by Tim Pearce)