Taiwan’s second squadron of US-made Apache AH-64E attack helicopters has gone into service as tensions build with Beijing. The 15 helicopters, known as the “tank busters”, were commissioned on Tuesday and joined the first batch of 14 AH-64Es stationed at the Longtan Air Base in Taoyuan, in northern Taiwan, the island’s defence ministry said. Taiwanese President Tsai Ing-wen said the commissioning of the Apaches was “an important milestone” in meeting the island’s “multiple deterrence” strategy to counter an invasion. Cross-strait relations have soured since Tsai, of the independence-leaning Democratic Progressive Party, became president in 2016 and refused to acknowledge Beijing’s one-China principle. Chinese President Xi Jinping takes pacifying line on Taiwan as hawks call for force Beijing considers Taiwan a breakaway province that must be brought back to the mainland fold, if necessary by force, and sees the principle as the foundation for cross-strait relations. It has suspended talks and exchanges with the island and increased its military presence near the island – including sending warplanes and warships for drills near or around Taiwan – to try to force Tsai to accept the policy. But Tsai has continued to resist Beijing’s pressure with support from Washington, which has been concerned about Beijing’s growing military expansion in the South China Sea and beyond. “The government will make sure to fully support the military to follow up and further enhance the helicopters’ capability,” Tsai said. Taiwan brought 30 AH-64Es from the United States for NT$60 billion (US$1.96 billion) in 2008 when Ma Ying-jeou was the island’s president. The helicopters were all delivered by October 2014 but one crashed during a training flight in April 2014, leaving 29 to form the 601st Brigade. We need more subs, says Taiwan, as it aims to bolster its naval defences in face of Beijing’s increasing belligerence The defence ministry said the first squadron of 14 helicopters was commissioned in June last year, and it took the army close to five years to train the personnel and complete the infrastructure needed for the brigade to be fully operational. A Taiwanese military source told the South China Morning Post that the US sent officers from Hawaii to observe the commissioning of the helicopters. “By stationing the two squadrons in Longtan, the military aims to allow the brigade to intercept an enemy’s landing corps that could make inroads into Taiwan from the north coast,” the source said, adding the squadrons could also be used to defend Taipei. The AH-64E is equipped with powerful target acquisition radar capable of 360-degree operation to a range of 8km. It can track 128 targets simultaneously and its 16 Hellfire missiles can be deployed in less than 30 seconds, according to the military.