China signed a significant 25-year Strategic Cooperation Pact with Iran in March 2021, solidifying a comprehensive partnership across economic, political, and security domains. This landmark agreement involves substantial Chinese investment in Iran's energy, infrastructure, and transportation sectors, estimated to be hundreds of billions of dollars. It also includes military cooperation and intelligence sharing, deepening the ties between the two nations and impacting regional geopolitics.
Pakistan is a close ally of China, particularly through the CPEC, but this specific 25-year pact was not with Pakistan. India has a complex and often competitive relationship with China, not one characterized by such a broad strategic pact. Sri Lanka has received significant Chinese investment but is not the signatory to this particular long-term strategic agreement.