Police found men carrying a huge amount of cash on Thursday night at Fukuoka Airport in southwestern Japan and are questioning them as potential suspects in an alleged heist worth 384 million yen ($3.5 million).

The manhunt for three suspected robbers came after a 29-year-old Tokyo man called the police earlier in the day claiming he had been robbed of the amount of cash after withdrawing the money from a bank in the Tenjin district of the city of Fukuoka.

The men, including one believed to be a South Korean national, were taken into custody at the international terminal of the airport, located in the city, investigative sources said, suggesting they were planning to flee the country with the money.

The man, a company employee from Tokyo's Adachi Ward, reported to the police he had been sprayed with a substance before the thieves grabbed the money from him in a parking lot across the street from a Mizuho Bank branch at around 12:25 p.m.

The Fukuoka prefectural police set up a 155-member task force to investigate the alleged robbery that occurred in an area bustling with offices and shops.

It is believed three people were involved in the robbery, with two, who were wearing white masks, attacking the man. One of the attackers was wearing gray working clothes, while another was clad in black working clothes with a white head covering, according to the police.

The third suspect was apparently waiting in a white van in the coin-operated parking lot. The victim was robbed of a carry-on bag containing the cash as he returned to his vehicle after leaving the bank.

The three all fled the scene in the van, which was parked just a few spaces away from the man's vehicle.

A woman who was in a building beside the parking lot said, "A man was shouting while chasing after the white van in the parking lot," adding the van was driven through the parking lot entrance barrier and into a narrow backstreet.

Another witness said the driver of the van was wearing a mask and the rear windows were tinted black.

A woman who was working in a shaved ice trailer near the parking lot said she heard screeching tires and saw a white van speeding off, and that she heard the man shout "thieves."

The man was quoted as telling police he was in Fukuoka on a business trip and the money was "for a deal." He also told investigators he works at a shop for precious metals in Tokyo and had planned to buy gold with the money he withdrew.

The police believe the three robbers had prior knowledge that a large sum would be withdrawn and are looking for accomplices. The man told the bank beforehand about the cash withdrawal.

He did not suffer any noticeable injuries in the incident, according to the police.

Last July, gold bars worth around 600 million yen were stolen near JR Hakata Station in the city while being transported to a cash-for-gold store.