Venezuela's Supreme Court has been attacked with a grenade thrown from a police helicopter in what the country's president, Nicolas Maduro, described as a "terrorist attack".

Speaking on state TV, the 54-year-old embattled leader said special forces were hunting those behind the attack, which follows three months of opposition protests and some dissent from within government ranks.

Reports said the grenade aimed at the court did not explode. The helicopter was also seen flying over the interior ministry, Mr Maduro said.

Venezuela Supreme Court attacker explains his motives

According to the government, an army officer who gave his name as Oscar Perez seized a helicopter and flew it over the city.

Video posted on social media showed the aircraft flying low over buildings in the capital. Loud bangs can be heard in the background.

The pro-government Supreme Court is particularly hated by Mr Maduro's opponents for its string of rulings bolstering his power and undermining the opposition-controlled legislature.

The socialist leader is pushing a vote on 30 July for a special super-body called a Constituent Assembly, which could rewrite the national charter and supersede other institutions such as the opposition-controlled congress.

Earlier, Venezuela's leader warned that he and supporters would take up arms if his socialist government was violently overthrown by opponents who have been on the streets since April. At least 75 people have died in the unrest.

"I'm telling the world, and I hope the world listens after 90 days of protest, destruction and death," he said.

"If Venezuela was plunged into chaos and violence and the Bolivarian Revolution destroyed, we would go to combat.