TAIPEI (Reuters) - Taiwan President Tsai Ing-wen will pledge to strengthen the island’s defences and work more with regional partners on security in a major speech on Saturday, at a time when tensions with its giant neighbour China have risen dramatically. Democratic Taiwan, claimed by China as its own territory, has come under increasing pressure from Beijing, which has ramped up air force activity near the island in the past few weeks including crossing the Taiwan Strait’s sensitive mid line that normally serves as an unofficial buffer zone. China says it is responding to “collusion” between Washington and Taipei, angered at growing U.S. support for the self-governed island which Beijing views as a precursor to Taiwan declaring formal independence, a red line for China. According to an outline of her national day speech on Saturday, as described to Reuters by a source briefed on its contents, Tsai will say that only solid determination and strength can guarantee security and maintain regional peace. Tsai, re-elected by a landslide in January on a promise to stand up to China, will emphasise military modernisation and the speeding up of “asymmetric warfare” capabilities, which refers to making any attack Chinese attack difficult and costly, for example with smart mines and portable missiles. Washington, which, like most countries, has no formal diplomatic ties with Taipei though it is its strongest global backer, has been pushing Taiwan to modernise its military so they can become a “porcupine”, hard for China to attack. Tsai has sought to work more closely with like-minded democracies, and she will say that Taiwan will “strengthen its security partnership role with surrounding countries” while protecting its democracy and sovereignty. Taiwan will also “proactively participate” in the building of a future new international and regional order, she will say. On relations with China, Tsai will say that Taiwan will stick to its principles and is “determined” to ensure stability, but that this is the responsibility of both parties.