By Chris Hogg
BBC Taiwan correspondent
China has made clear that it opposes all official exchanges between the United States and Taiwan.
Taiwan buys most of its weapons from the US
Members of Taiwan's legislature are currently visiting Washington to discuss plans for an $18bn arms deal for the island.
The Bush administration says Taiwan needs to buy the weapons to boost its defences.
China sees Taiwan as a renegade province, to be allied to the mainland by force if necessary.
China's latest verbal salvo against the Taiwanese was launched at a regular press conference by the Taiwan Affairs Office in Beijing.
Spokesman Li Weiyi complained that separatists on the island were trying to oppose reunification with China.
He said China was against any official exchanges or military co-operation between the US and Taiwan.
Meanwhile, Taiwanese lawmakers have embarked on a tour of military facilities in the US, and will hold meetings at the Pentagon to discuss a proposed arms deal.
The deal includes submarines, anti-submarine aircraft and missile systems, which the US says are vital if Taiwan is to defend itself.
Taiwan test-fired two US-made Patriot missiles this week.
China plans to hold military exercises on an island on its south-eastern coast later this month.
Reports suggest a mock invasion of Taiwan will be carried out during the manoeuvres.
The Chinese state media has also claimed that pro-independence forces in Taiwan might launch terrorist attacks on the mainland.
There seems little evidence to back up the claims, suggesting they are simply a new effort to undermine the leadership of Taiwan's President Chen Shui-bian.