NEW accusations have surfaced of Vietnamese backed by naturalised Americans plotting to topple the Hanoi Government from Cambodia. The claims came as Vietnam yesterday confirmed the expulsion of two Vietnamese-Americans jailed for trying to overthrow the Communist Party leadership. The Interior Ministry told US diplomats to get Nguyen Tan Tri and Nguyen Quang Liem out of the country by tomorrow. The two are in Ho Chi Minh City's maximum security Chi Hoa prison. They will be freed on their return to the US, with Washington refusing to accept they have committed any crime. A Foreign Ministry spokesman said their release was made at the request of the US. Senior State Department officials had repeatedly said the pair's detention was interference in non-violent politics, and the case loomed as a sticking point in new Hanoi-Washington ties. It comes ahead of several high-profile US visits to Hanoi this month, including a historic tour by former defence secretary Robert McNamara, the architect of US military involvement in Vietnam. Tri and Liem were sentenced in August with seven other members of the Tan Dai Viet Party, outlawed since communists took Saigon in 1975. The group members were all arrested in 1993 as they returned to Ho Chi Minh City to hold a conference on democracy. Meanwhile, in Cambodia, the Interior Ministry said anti-communists were plotting the overthrow of the Hanoi Government. The groups are said to have up to 2,000 supporters and to be armed in a country where weapons are readily available, though the Cambodian Government has pledged to act against them. 'It does exist, we are taking measures against it,' Cambodian Interior Minister You Hockry said of the plot. A Vietnamese diplomat named two of the groups as Chinh Phu Vietnam Tu Do [Free Vietnam Government] and Chinh Phu Vietnam Phuc Quoc [Government for Vietnamese Restoration]. The Phnom Penh Post reported the groups had been operating in the capital for more than a year. It quoted unnamed sources as saying they were led by former generals of the pre-1975 South Vietnam army, many of whom found refuge in the US when the communist north reunified the country in 1975. US Ambassador to Cambodia Charles Twining said Washington was against 'any group that interferes with Vietnam's improved relations with the world. 'If you want to change the country, you have to work peacefully'. Another US diplomat said: 'We're aware of these groups, we don't agree with their goals and we have good relations with Cambodia and Vietnam and don't want to do anything to harm those relations.' A Vietnamese spokesman who saw documents from the anti-Hanoi groups estimated their strength at 400 to 500 and said they might possess weapons.