NEW DELH/COLOMBO, Jan 24 (Reuters) - The Export-Import Bank of China has offered Sri Lanka a two-year moratorium on its debt and said it will support the country's efforts to secure a $2.9 billion loan from the International Monetary Fund, according to a letter reviewed by Reuters. (Reporting by Devjyot Ghoshal and Uditha Jayasinghe; Editing by Jacqueline Wong)