SINGAPORE - Drugs worth more than $316,000 were seized in two operations by the Central Narcotics Bureau (CNB) on Monday.

Five Singaporean men were also arrested.

The haul of drugs included more than 5.2kg of cannabis, 1.6kg of heroin and 139g of Ice, or methamphetamine, said CNB in a press release on Tuesday.

The first operation took place in the vicinity of Sims Drive, where CNB officers were tailing a suspected drug trafficker believed to be dealing in a large amount of cannabis.

At about 4.40pm, the officers spotted the 43-year-old Singaporean male in the void deck of an HDB block with a 41-year-old man. Both were arrested.

Officers found 170g of cannabis after searching the trafficking suspect. They also raided his drug store in an HDB flat at Sims Drive and found about 5kg of cannabis and 139g of Ice.

In the second operation, CNB officers were at Simei to nab a 48-year-old taxi driver suspected of drug trafficking.

He was spotted shortly after 5 pm and followed to the vicinity of a carpark in a housing estate in Geylang Bahru.

Another trafficking suspect, a 64-year-old male got in the taxi but soon alighted. He was arrested promptly and about 239g of heroin was recovered from him.

Other officers then intercepted the taxi along Serangoon Road and arrested the driver.

A video was put up on citizen journalism website Stomp of the chase, which involved "six to 10" officers tailing the taxi on cars and motorcycles.

Officers found about 1.4kg of heroin and a small amount of Ice in the taxi. About $2,200 in cash was also seized from him.

Upon further investigation, officers went on to raid a flat in Choa Chu Kang, believed to be the hideout of an associate of the taxi driver's. Officers arrested a 52-year-old male and recovered some 82g of Ice, 7g of heroin and a digital weighing scale.

Investigations are ongoing. The suspects could face the death penalty if convicted.