The policy affirms the Chinese position that there is only one China and Taiwan is part of it.
Taiwan made informal contacts with the new government in an attempt to secure a change of policy, senior Gambian government officials told Reuters. Senior Chinese officials attended new president Adama Barrow's swearing-in ceremony.
For years, China and Taiwan have tried to poach each other's allies, often dangling generous aid packages in front of leaders of developing nations.
"The government ... shall remain resolute in upholding the 'one China' policy and fully support all efforts by the Chinese government to unify its rightful territory," it said in a statement," it said in a statement late on Sunday.
Barrow defeated Jammeh in an election in December. Jammeh had held power for 22 years and only stepped down in January as thousands of West African troops who had entered the country were poised to enter the capital.
China resumed ties with former Taiwan ally Gambia in March last year. São Tomé and Príncipe followed and switched recognition to Beijing in December.
In Africa, only Burkina Faso and Swaziland now recognize Taiwan, viewed by China as a wayward province to be recovered by force if necessary.
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