Three Thai hostages held by Hamas militants were released from Gaza on Sunday, taking the number of Thai nationals freed since the four-day truce began on Friday to 17.

"We were the sole party that spoke to Hamas since the beginning of the war to ask for the release of Thais," Thai-Iran Alumni Association President, Lerpong Syed told Reuters on Monday.

Lerpong is part of a group of Thai Muslims convened by the country's parliamentary speaker Wan Muhammad Noor Matha, which travelled to Tehran in October and spoke with Hamas representatives.

"If Thailand only relied on the foreign ministry or asked other countries for help - the chances of getting released with the first group would be very low," he said, adding that other countries with hostages such as the United States, Germany and France have more influence.

The group conveyed to Hamas during a three-hour meeting that Thais were not party to the conflict and should be freed, he said, after which the Palestinian militant group gave their assurances that Thais would be released first and unconditionally once there was a ceasefire.

The temporary truce is first halt in fighting in the seven weeks since Hamas killed 1,200 people and took about 240 hostages back into Gaza.

Before the war, around 30,000 Thai labourers worked in Israel's agriculture sector, making up one of the largest migrant worker groups in the country.

"Our team hit the right spot from the beginning by going to Iran and talking directly to Hamas," said another member of the Thai group, veteran politician Areepen Uttarasin.

However, a source briefed on the talks said the hostage agreement was mediated by Qatar and Egypt in a negotiation track that was opened when Thailand's foreign minister visited Qatar on Oct. 31.

Iran has also said it facilitated the release, while Hamas has said the release was due to the efforts of Turkish President Tayyip Erdogan.

"For the remaining 15 Thai hostages, the Royal Thai Government continues to exert all efforts towards their safe release at the earliest opportunity," the Ministry of Foreign Affairs said in a statement on Monday.

When asked about parallel efforts, Lerpong said: "My responsibility is to bring Thais home and if (other governments) want to have a say, that's fine. I consider I accomplished my mission."

Thailand's population of 70 million are predominantly Buddhist and have largely co-existed peacefully with its Muslim minority.

(Additional reporting by Panarat Thepgumpanat; Editing by Tom Hogue and Lincoln Feast)

By Chayut Setboonsarng