NEW DELHI, JUNE 14 (SUNDAY) -- Presumed Sikh gunmen killed at least nine persons and wounded 22 in New Delhi, in the most serious extremist attack in this capital for two years.

The Press Trust of India (PTI) news agency said two teams of gunmen struck in four separate residential areas of south Delhi, opening fire with machine guns and lobbing hand grenades at random. Police Commissioner Ved Marwah said the city had been put on top alert and guards were stationed at all exits.

Although the attackers have not been identified, PTI said they were believed to be Sikh extremists, against whom the Punjab police yesterday claimed a major success by breaking up seven gangs and arresting 27 people.

Police said gunmen attacked a wedding party in Greater Kailash, a wealthy suburb. They burst into the house of Rajesh Behl, a building contractor, and opened fire on the family and guests with machine guns, killing at least four people and injuring 20. They threw a grenade but it failed to explode, police said.

The gang commandeered a car, shooting its three occupants and driving to a nearby shopping complex, where they shot bystanders.

Meanwhile, according to police, a second team of gunmen opened fire at Garhi village in Lajpat Nagar, close to the capital, and at Tughlakabad suburb. The total killed there was not yet known, and doctors tending the victims said more were likely to die.

The attacks were the most serious in the Indian capital sincemid-1985, when Sikh extremists were blamed for a series of bombs concealed in radios that killed at least 70 people.

Since then, Sikh separatist violence had occurred mainly in Punjab state, where in recent months Sikhs have killed their opponents at the rate of two per day. Last month the government of Prime Minister Rajiv Gandhi more directly confronted the extremists by dismissing the moderate Sikh government in Punjab, imposing federal rule and toughening security there.