Taipei, Aug 5 (IANS): Taiwan's Defence Ministry on Friday said that Chinese warships and aircraft conducted military drills in waters near the island, as tensions escalated in the region following US House Speaker Nancy Pelosi's visit earlier this week.

In a statement, the Ministry said that China's People's Liberation Army (PLA) forces crossed the median line -- the halfway point between the island and mainland China -- in a move it called a "highly provocative act", reports CNN.

The line has previously been an informal but largely respected border of control between Beijing and Taipei.

Taiwan's military responded with radio warnings and put air patrol forces, naval ships and shore-based missile systems on alert, the Ministry added.

On Friday, Taiwan's Premier Su Tseng-chang said the island represented "freedom and democracy", and that "the evil neighbour next door flexed its muscles on our doorstep and arbitrarily sabotaged (one of) the busiest waterways in the world with military exercises".

The skies and waters around Taiwan have become a focal point as Beijing ramps up tensions not only with Taiwan, but with neighbouring Japan, which lodged a formal protest with China after five projectiles landed in Japan's Exclusive Economic Zone (EEZ).

The missiles were among a number launched by Beijing Thursday, some of which flew over Taiwan, as Pelosi made her way to Tokyo where she met Japanese Prime Minister Fumio Kishida on Friday, CNN reported.

China has previously fired missiles into waters surrounding Taiwan, a democratic island of 24 million that the Chinese Communist Party regards as its territory, despite having never controlled it, most notably during the Taiwan Strait Crisis in the 1990s.

But missiles flying over the island marked a significant escalation, with US officials warning there may be more to come.