Paraguay's president-elect Santiago Pena has pledged to Taiwanese President Tsai Ing-wen that his country will maintain diplomatic ties with Taiwan.

Pena won the presidential election in April, beating an opposition coalition candidate who hinted at establishing diplomatic ties with China. Paraguay is the only country in South America that has diplomatic ties with Taiwan.

Pena met Tsai on Wednesday during his visit to Taiwan ahead of his inauguration in August. Wednesday marks 66 years since Paraguay and Taiwan established diplomatic ties.

Tsai said it is significant that she can celebrate the anniversary with Paraguay's future president in Taiwan.

She said she expects Taiwan and Paraguay to stand together "on the frontline of free democracy in the face of the expansion of authoritarianism."

Pena said he reiterates his personal and his country's commitment to stand by the people of Taiwan for the next five years.

Taiwan plans to send a high-level delegation to attend Pena's inauguration ceremony in Paraguay next month.

Nine countries have severed diplomatic ties with Taiwan since Tsai took office in 2016. Five of them are in Latin America, such as Nicaragua and Honduras.

Taiwan now has diplomatic relations with 13 countries.