The pleas came as police in Thailand announced they had detained another Hmong American suspected of being an associate of Vang Pao near the Thai-Lao border.
The man, identified as Sha Wang Lee, 53, carried a US passport and was being taken to the US embassy in Bangkok to verify his identity and to determine whether the US wanted him repatriated, police said.
Officials said the man was carrying a certificate signed by Vang Pao saying he had undergone military training.
Charismatic, 77-year-old military leader variously described as "fearless" and a "warlord"
Fought CIA-backed war against Pathet Lao communists
Fled to US following communist victory in 1975, became influential figure in Hmong exile community
Campaigned against Lao government and raised funds for Thailand-based resistance movement
Improved ties between Laos and Thailand as well as US dried up support for resistance
Vang Pao is a prominent member of the Hmong community in California. During the war he served in a secret army funded by the CIA to fight North Vietnamese and Pathet Lao forces.
Aside from him and the nine other ethnic Hmong, also charged in the case is Harrison Jack, a 60-year-old former Army Ranger who led covert operations and worked with Hmong fighters during the Vietnam War.
The charges have rocked the Hmong exile community in the US, which includes thousands of refugees who fled Laos following the 1975 communist takeover.
On Monday, a crowd of 1,200 to 1,500 demonstrated peacefully outside the federal courthouse in and the state capitol in Sacramento, California.
The Hmong, who fought on the side of the US during the Vietnam War, say they feel betrayed that the US government has not done enough to stop what they say is the persecution of Hmong in Laos and has instead turned on their leaders in the United States.
"When they [the US] pulled their military out, we were left for dead," Nikki Heu, one of the protestors, told the Associated Press.
The 11 are charged with conspiring to violate the Neutrality Act against a nation with which the United States is at peace; conspiracy to kill, kidnap and maim; conspiracy to possess firearms and destructive devices; and conspiracy to export munitions without a State Department license.
Prosecutors say the defendants intended to buy nearly $10m worth of weapons from an undercover federal agent posing as a weapons broker in February.
Judges have refused to set bail during previous hearings, saying each defendant could be a flight risk or pose a danger to society.
|Thousands of Hmong fled Laos after the war |
and many resettled in the US [GALLO/GETTY]
After the war ended in 1975 many Hmong resettled in the US while others went to Thailand, where they live in refugee camps.
But the Thai authorities, who recently struck a deal with Laos to return Hmong to Laos, deported 161 refugees over the weekend, ignoring calls from the United Nations urging a halt to deportations until their claims for refugee status were individually assessed.
Many Hmong say they fear they will be tortured in Laos for backing the US against the communists and say they would rather die than be sent back.
The US state department has criticised Thailand for the repatriations and urged the government to screen people being returned so that those who might be persecuted would not be sent back.
Human rights and exiled groups accuse the Lao military of waging a war against Hmong living in the Xaisomboun "special zone" as punishment for their alliance with the US.
The region is off limits, but Western journalists who secretly entered the area in 2003 returned with pictures of malnourished, wounded and disfigured fighters and their families.