
"The Lao government is notorious for treating deported Hmong harshly upon their return," said Bill Frelick, the group's refugee policy director.
"By imprisoning these Hmong deportees, Lao authorities confirm the fear many Hmong asylum seekers and refugees have expressed of being persecuted if returned to their native country."
HRW said more than 5,000 of the 8,000 Hmong in June marched out of Huay Nam Khao refugee camp in Thailand's Phetchabun province to protest a wave of arrests and deportations of Hmong refugees.
Thailand has since 2005 repatriated more than 1,500 of the 8,000 Hmong residents of the Thai camps, while both Bangkok and Vientiane have rejected requests by the UN refugee agency or other groups to monitor the process.
According to HRW, witnesses recently confirmed to them that Lao authorities held at least some of the leaders in a prison in southern Laos for more than three months before finally releasing them.
According to these witnesses, those leaders looked malnourished. Their treatment by Lao authorities and conditions of detention remain to be determined. The whereabouts of the remaining leaders - Chia Yang, Phia Lee, Nyia Ma Vue, Phaya Vue, and Xai Toua Yang - is still unknown.
The report said since November 2005, the Thai government has sent 1,580 Hmong asylum seekers and refugees back to Laos.
A July 1, 2008 statement by the Thai Ministry of Foreign Affairs, these were all voluntary returns of economic migrants. But HRW also pointed out that the Thai government has prevent the international community from conducting a legitimate screening of Hmong asylum seekers, some of whom show scars from bullet wounds suffered during Lao military operations.
"Thailand's forcible, secret return of Hmong refugee camp protest leaders to Laos is a clear violation of international refugee law," said Frelick.
"And, as long as both Laos and Thailand deny the UN High Commissioner for Refugees access to the Hmong, these so-called voluntary returns cannot be believed to be truly voluntary."
Witnesses of some Thai deportations of Hmong have reported that Thai authorities forcibly separated families as they pushed Hmong asylum seekers onto trucks. Other sources indicate many Hmong asylum seekers agreed to return to Laos only after being kept in fear and uncertainty for years by Thai authorities.
"It is ludicrous and intimidating to require that a refugee who qualifies for resettlement should first have to return to the country where he fears persecution before being allowed to resettle," said Frelick.