BEIJING, Jan 31 (Reuters) - China's foreign ministry on Tuesday condemned a phone call between Czech President-elect Petr Pavel and Taiwan President Tsai Ing-Wen, accusing Pavel of going back on his word and lacking credibility.

Tsai held a call with Pavel on Monday, a diplomatic breakthrough for the China-claimed island, which has no formal relations with Prague.

Chinese foreign ministry spokesperson Mao Ning told a regular news briefing that China expressed strong dissatisfaction and firm opposition to the call, and that it had made stern representations to the Czech side.

Mao also questioned Pavel's credibility for what she described as a change in his position that Beijing's claims over the self-ruled island should be respected.