Authorities say the men contributed from S$60 ($45) to S$1,360 ($1,000) to fund attacks in the name of Islamic State in Bangladesh (ISB), reports Reuters. It was Singapore's first case of terrorism financing.
The report quoted the prosecutor, who did not give his name for security reasons, as saying, "The amounts were significant relative to the salaries of the accused persons."
The sentences would send a "strong message that every and all terrorism financing will be dealt with", the prosecutor said.
The men had been detained in April under the country's Internal Security Act (ISA), which allows suspects to be held for lengthy periods without trial.
They are Mizanur Rahman, 31, a draftsman earning S$1,800 ($1,300) a month, Rubel Miah, 26, Md Jabath Kysar Haje Norul Islam Sowdagar, 31, and Ismail Hawlader Sohel, 29.
The four had pleaded guilty on May 31 to one or two counts each of providing or collecting hundreds of dollars to fund terror attacks in Bangladesh, says a Channel NewsAsia report.
It said they had also been charged with providing or collecting money to buy weapons and wage an armed jihad in Bangladesh.
Rahman, found to be the ringleader, has been sentenced to five years in jail, reported Reuters, The Straits Times and Channel NewsAsia on Tuesday.
"I wanted to learn my religion but they show me the wrong way, the wrong activities," Mizanur said in court, according to the Reuters report. "My intentions were wrong ... I'm very remorseful."
Sohel will be behind bars for two years, while Rubel and Jabath have been sentenced to two and half years in jail.
Bangladesh, a deeply religious but mostly moderate Muslim-majority country of 160 million people, has faced a series of militant attacks over the past year, the most serious on July 1 when gunmen stormed a cafe in the capital, Dhaka, and killed 22 people, most of them foreigners.
On the other hand, wealthy, multi-ethnic Singapore has not faced any successful militant attacks in decades. There were no indications the men had planned to carry out attacks in Singapore.
The Straits Times report said the sentences would have retrospective effect from May 27, the day the men were first produced in court.
Asking for deterrent sentences, the report said, the prosecution had pointed out that these men caused public disquiet and were funding terrorist organisation Islamic State, also known as IS or ISIS.
The four were among six charged under the Terrorism (Suppression of Financing) Act (TSOFA).
The other two - Daulat Zaman, 34, and Leakot Ali Mamun, 29, - have denied the charges and face criminal trial, said the Straits Times report.
Channel NewsAsia reported that Zaman had claimed he did not know that the money he contributed would be used for terrorist activities.
However, it said, other members of the group admitted they had pledged allegiance to ISIS leader Abu Bakar al-Bagdadi alongside Zaman in January.
The remaining two of Rahman's group, Ibrahim Sohag and Shariful Islam, both 24, have yet to be charged and remain in detention, reported Reuters. No other details were given.
The punishment for financing terrorism in Singapore is up to 10 years in jail and a fine of up to S$500,000, or both.
According to the court documents cited by the Straits Times report, the four convicts had precise roles.
They were led by Rahman, with Mamun as the group's deputy leader. Rubel used to handle finances, and Jabath worked on the group's publicity matters.
Zaman and Sohel were part of the group's security and fighter units, respectively, the report said.
Miah and Jabath had also been accused of being in possession of money meant for funding terrorist activities.
According to the report, court papers had revealed that Jabath possessed $1,360, including $1,060 given to him by Rubel.
The six were among eight marine and construction industry workers arrested between March and early April, according to Singapore's Ministry of Home Affairs (MHA). They called themselves the Islamic State in Bangladesh.
The court found they were planning attacks in Bangladesh with the aim of toppling the country's government.
Their goal was the setting up of an Islamic state in Bangladesh and to make it a part of the so-called caliphate of the Islamic State in Iraq and Syria (ISIS), said the Straits Times report.
Channel NewsAsia report quoted the prosecution as saying in court, "Much havoc can be wracked with inexpensive items. The cost of a terrorist act can be modest, but the cost to society is far greater.
"Singapore must take a firm stance against terrorism and terrorism financing."
The report said prosecutors had held ringleader Mizanur Rahman responsible for setting up the group after developing a 'liking' for ISIS.
They said Mizanur had tried to join ISIS three times. When he was unable to obtain a visa to travel to Turkey and Algeria, he travelled to Singapore instead and later recruited the others.
The Islamist cell used meet in parks and open fields and shared radical propaganda and videos, the MHA said earlier. The ISB was the first group comprising all foreigners to be detained under the ISA in Singapore.
After their arrests in April, the MHA in a statement had said that Rahman was a medium-skilled worker holding an 'S' category permit, while the others were semi-skilled.
Five other Bangladeshis, who attracted the attention of the authorities during the investigation were sent home in April and arrested upon their return.
Police in Bangladesh said they were being investigated for connections to the banned militant group Ansarullah Bangla Team.
Source: Bangladesh's First Internet Newspaper