WASHINGTON: There is a need to review the barter trade system between Sabah and southern Philippines, following the kidnapping of four Malaysians on Friday in the area. Deputy Prime Minister Datuk Seri Dr Ahmad Zahid Hamidi (pix) said the barter trade system was seen as benefiting only one side, and did not favour Malaysia. Apart from that, it also involved smuggling of subsidised goods from Malaysia which caused leakages in national revenue, he told Malaysian journalists here on Saturday. "I am not against the policy but from the operational aspect, we can see it is favouring only one side," he said. Ahmad Zahid is currently on a week-long visit to the United States since March 29, to attend a two-day Nuclear Security Summit which ended on Friday. He said on this aspect of barter trade system, the government agencies responsible should review the operating system via several small ports in Sabah and southern Philippines. "The time has come for several agencies and departments under the ministries involved in barter trade to study quickly so that the issue of favouring only one side could be averted." Ahmad Zahid, who is also home minister, said considering the routes were high risk, Malaysian traders passing the area had been advised to inform the Marine Police, Malaysian Maritime Enforcement Agency (MMEA) and Royal Malaysian Navy to protect them. "As they comprised traders of goods to Philippines, they are aware of the risk when passing through several areas which have been zoned as dangerous spots. "They should inform the security forces, especially marine police to patrol when entering waters of other countries," he added. On the kidnapping of the four Malaysian crew members of a Malaysian-registered tug boat - MV MASSIVE 6 - Ahmad Zahid said so far, there was no information on their status and the motive was believed to be for ransom. The deputy prime minister said they (the kidnappers) were collecting ransom to fund their activities as terrorists and this was very worrying because Malaysia was seen as if allowing violence to continue. "The trend is clear ... of the 10 crew members on the boat, Myanmars and Indonesians were released while Malaysians were captured. This is clear they are trying to obtain ransom. "Initial investigations revealed they were suspected to be from the Philippines and were Muslims, and this tarnished the image of Islam and should be avoided. "I was informed by the Sabah police commissioner that several efforts were in operation to secure their safe release," he said, adding there was no demand for ransom so far. Ahmad Zahid said however, based on their modus operandi, the kidnappers would sell their victims to another group and the group would in turn, sell them to another at a higher price. "We understand the modus operandi and we hope it will not happen like that. The most important thing is the safety of our people at their captive site." The four Malaysians have been identified as Wong Teck Kang, 31; Wong Hung Sing, 34; Wong Teck Chii, 29 and Johnny Lau Jung Hien, 21. "They are from Sarawak and we hope they will be released as soon as possible. "We hope families and relatives of the kidnap victims will be patient and our security forces, especially the police, will give top priority to secure their release," said Ahmad Zahid. He hoped the people will not make any comment on the matter. "Leave it to the police to find a way to secure their safe release," he said.