By Jill McGivering BBC News

China has long threatened to use force against Taiwan

There has been alarm and anger in Taiwan about China's new anti-secession law, but the imprecise wording of the law has also sparked confusion about how exactly it might be applied and how best to read China's intentions.

This new law formalises a right China has long asserted - to use military force against Taiwan if it declares independence.

At a time of growing suspicion in Beijing about Taiwan's President Chen Shui-bian, China is drawing a fresh, high-profile line in the sand.

It is a clear warning to President Chen to exercise care in his second term.

China is alarmed by his forthcoming plans to amend Taiwan's constitution, despite his assurances this is not a covert way of pursuing independence.

The Chinese premier says this is not a piece of war legislation

One of the difficulties for Taiwan is the vague wording of the law. Conflicting signals from China's leadership have not helped.

On Sunday, President Hu Jintao's instruction to the military to be prepared for war caused understandable alarm in the region.

But on Monday, Prime Minister Wen Jiabao sounded more reassuring. He told reporters the new law was not a piece of war legislation.

The threat of "non-peaceful means" enshrined in it would only be a last resort, he said. And he emphasised the importance of the rapidly growing economic and cultural ties between Taiwan and the mainland.

The law clearly stipulated, he said, that those ties should still be encouraged and promoted.

This week China also saw a final step in the handing over of power from former President Jiang Zemin to the current leadership.