BEIJING — Burkina Faso and China formally established diplomatic ties on Saturday, days after the West African nation broke off relations with Taiwan, the self-governing island that Beijing has been trying to isolate on the global stage.

Burkina Faso’s decision was the latest blow to Taiwan, which Beijing considers part of its territory. The island is now left with 18 diplomatic allies — many of them poor nations in Central America and the Pacific, like Belize and Nauru; only one is in Africa, the tiny kingdom of Swaziland.

It was the second ally to break with Taiwan in less than a month, as China’s economic clout and geopolitical influence have made it difficult for countries to maintain alliances. The Dominican Republic established diplomatic relations with Beijing this month, citing hopes for improved commercial ties.

The Chinese Foreign Ministry said a document establishing diplomatic ties was signed on Saturday in Beijing between Wang Yi, the state councilor and foreign minister, and Burkina Faso’s foreign minister, Alpha Barry.