BEIJING (Reuters) -China is willing to begin talks on a free trade agreement with Honduras "as soon as possible", Chinese President Xi Jinping said on Monday, during the first visit by the Central American country's president since forming diplomatic ties in March.

Honduras' President Xiomara Castro is on a six-day official visit to China. She launched diplomatic relations with Beijing after cutting ties with Taiwan. The country is also seeking support from China to mitigate its debt burden.

"You have resolutely fulfilled your election promise of establishing diplomatic relations with China, made a historic decision, and demonstrated your firm political will," Xi told Castro during talks in Beijing.

China will actively promote Honduran products to enter the Chinese market, Xi was quoted as saying by state broadcaster CCTV.

Chinese customs said on Monday it had approved the import of Whiteleg shrimp from Honduras.

China also encourages Chinese enterprises to participate in Honduras' projects in areas including energy, infrastructure and telecommunications, CCTV cited a joint declaration as saying.

The Honduran side is willing to provide policy support and facilitation, CCTV reported.

The Chinese leader also emphasised that both sides should deepen political mutual trust, and uphold the "One-China" principle.

"One-China principle is the primary premise and political foundation for the establishment of loyal diplomatic relations and the development of bilateral relations," Xi said.

When Honduras ended its decades-long relationship with Taiwan, the island's foreign minister accused it of demanding exorbitant sums before being lured away by Beijing.

China claims democratically ruled Taiwan as its own territory with no right to state-to-state ties, a position Taipei strongly rejects. China demands that countries with which it has ties recognise its position.

The Honduran foreign ministry said at the time it recognised the People's Republic of China as the only legitimate government that represents all of China and that Taiwan was an "inseparable part of Chinese territory".

The United States is watching with concern as China expands its footprint in its backyard by taking away Taiwan's Central American allies, and has repeatedly warned countries not to believe China's promises of aid.

Xi said that China supports Honduras' "independent choice of development path in line with its national conditions", and opposes any external interference in the Central American country's internal affairs.

(Reporting by Ella Cao and Liz Lee; editing by Robert Birsel and Sharon Singleton)