NAIROBI, Jan. 31 (Xinhua) -- Kenyan police on Wednesday launched investigations into an incident where unknown gunmen hurled a grenade and fired shots at opposition leader, Kalonzo Musyoka's residence on Tuesday night.

Karen divisional police commander Cunningham Suiyanka confirmed the incident, saying no one was injured during the 2 a.m. incident at the former vice-president's lush Karen home. The gunmen also allegedly shot at the gate.

The former vice president was at home at the time of the incident but Suiyanka said police will issue a comprehensive statement once investigations are complete.

Detectives from the Bomb Squad Unit have been deployed to the home of Musyoka who is also one of the co-principals in the National Super Alliance (NASA) which is being led by Raila Odinga.

The police said the attackers arrived there on board a private car and drove past the main gate after realizing there were private guards on duty.

They later made a u-turn meters ahead and stopped opposite the gate, hurled the grenade into the compound before shooting several times. The grenade reportedly hit a security wire on the perimeter wall and bounced back exploding.

The police said the attackers drove off soon after the incident. Musyoka's aide said they collected the spent cartridges and the grenade safety pin as evidence to the attack. Police rushed to the scene soon after the news of the attack went out.

The incident took place hours after security seconded to Musyoka and other NASA principals had been withdrawn on Tuesday over unexplained reasons.

This was ahead of the planned swearing-in of Raila Odinga and Musyoka as the "people's president and deputy president" respectively on Tuesday. However, Musyoka did not show up.

He later expressed its commitment to the opposition's quest for electoral reforms and accountable leadership despite his absence from the oath taking ceremony.