BANGKOK : Thai prosecutors dropped charges against the five-man crew of an aircraft accused of smuggling weapons from North Korea, saying Thursday the men might be guilty but would be deported to preserve good relations with their home countries.

The Attorney General's Office said the decision was made after the governments of Belarus and Kazakhstan contacted the Thai Foreign Ministry and requested the crew's release so they can be investigated at home.

"To charge them in Thailand could affect the good relationship between the countries," said Thanaphit Mollaphruek, a spokesman for the Attorney General's Office. "We have decided to drop all the charges and deport them."

The decision is likely to spark international criticism. The weapons' ultimate destination remains a mystery, though Thailand has said it may have been Iran. Experts have also voiced concern that authorities in the former Soviet republics have turned a blind eye to illicit activities of air freight companies that use Soviet-era planes to fly anything, anywhere for a price.

The crew was arrested Dec. 12 when the Ilyushin Il-76 cargo plane they were flying from the North Korean capital Pyongyang landed in Bangkok. Thai authorities, acting on a tip from the United States, found 35 tons of weapons on board — a violation of U.N. sanctions against North Korea.

"To charge them in this case would not be a benefit to Thailand," Thanaphit told a news conference, saying the men had planned to transit the weapons through Thailand and had no intention of using them in the country. "They were only here for refueling."

The U.S. Embassy had no immediate comment, spokeswoman Cynthia Brown said.

The crew — four Kazakhs and a Belarusian — left the prison where they were being held Thursday evening. They were to be turned over to immigration police who would arrange their deportation, said lawyer Somsak Saithong.

The U.N. imposed sanctions in June banning North Korea from exporting any arms after it conducted a nuclear test and test-fired missiles. North Korea is believed to earn hundreds of millions of dollars every year by selling missiles, missile parts and other weapons to countries such as Iran, Syria and Myanmar.

The crew has denied knowledge of arms aboard the plane, which Thai authorities say included explosives, rocket-propelled grenades and components for surface-to-air missiles. The crew says they believed they were carrying oil-drilling equipment.

"We are not saying that they're not guilty, just that we will not indict them in Thailand," Kayasit Pissawongprakan, director-general for the Attorney General's criminal litigation division, told reporters.

Hugh Griffiths, a researcher at the Stockholm International Peace Research Institute, said it is unlikely the men will be prosecuted in Kazakhstan.

"There have been very, very few prosecutions for brokering arms or transporting arms to or from embargoed destinations. Certainly there have been none in Kazakhstan," he said.

"It would be a first for the Kazakh authorities to prosecute anyone associated with those air cargo companies that are registered by their authorities, which have been documented again and again in United Nations sanctions committee reports," he said.

The crew was initially charged with five counts relating to illegal arms possession, but Thai authorities had repeatedly said the charges were expected to be stiffened once an investigation wrapped up.

In recent weeks, however, the tone from Thai authorities changed.

Foreign Minister Kasit Piromya indicated earlier this month that the men would be released, saying the government had "suggested to the office of the Attorney General to release them because the U.N. resolution does not oblige Thailand to ... bring up charges on the pilots and the crew."

A Thai government report to the U.N. Security Council leaked to reporters in late January said the aircraft was bound for Tehran's Mahrabad Airport.

But Thai government spokesman Panitan Wattanayarkorn subsequently said "to say that the weapons are going to Iran, that might be inexact."

Iran's Foreign Ministry has denied the weapons were destined for Iran, saying it has no need to import such arms because of its own sophisticated weapons production capability.

Investigations by The Associated Press in several countries showed the flight was facilitated by a web of holding companies and fake addresses from New Zealand to Barcelona designed to disguise the movement of the weapons.