Taiwan President Tsai Ing-wen will visit Eswatini, the island’s only diplomatic ally in Africa, next month to firm up ties, her office said Friday.Tsai will head to Eswatini on September 5, and attend celebrations marking the African nation’s independence day and King Mswati III’s birthday during the visit, her spokeswoman Olivia Lin said.She will hold a meeting with the king, visit a local hospital and Taiwan-sponsored projects before returning to Taipei on September 8.Lin told reporters that the visit is aimed at strengthening cooperation and shows the importance Taiwan attaches to “staunch ally” Eswatini.Eswatini, formerly known as Swaziland, is among only 13 countries that officially recognise Taiwan over China, which claims the self-ruled island as its own territory.It is also Taiwan’s last diplomatic ally in Africa, after Burkina Faso ditched Taipei in favour of Beijing in 2018.China has poached nine of Taiwan’s diplomatic allies since Tsai came to power in 2016 as relations have worsened.It has also ramped up military pressure.In April, it conducted military exercises to simulate the encirclement of the island after Tsai met US House Speaker Kevin McCarthy in California.As Tsai’s African visit was announced on Friday, Taiwan’s defence ministry said it had detected 22 Chinese warplanes around the island since 7 am (2300 GMT Thursday).The ministry said 13 of them either crossed the median line of the strait that separates Taiwan from mainland China, or entered the island’s air defence identification zone (ADIZ).The aircraft conducted “joint combat patrol” with five warships around Taiwan, it said. Beijing also staged military drills earlier this month after Taiwan’s Vice President Lai Ching-te returned from a visit to Paraguay with two US stopovers, and banned mango imports from the island.