A top Shanghai official Tuesday defended his controversial visit to Taiwan as "open and transparent" as protesters burnt his photo and accused him of promoting the island's unification with China.

Sha Hailin, a standing committee member of the Communist Party in the city and head of the United Front Work Department there, arrived on Monday for a forum on municipal exchanges.

He is the highest-level mainlander to visit since cross-strait ties worsened under Taiwan's new government.

"Expel Sha Hailin!" about 100 angry protesters shouted outside a hotel in Taipei where the forum is taking place, tearing down and burning photos of Sha and Taipei mayor Ko Wen-je.

Protesters had also rallied at an airport and other locations Sha visited Monday, shouting slogans against communism and for independence for Taiwan.

"For my visit... there is no 'secret deal' as some people claim. Everything is open and transparent," Sha said in response to the protests.

"The journey for peaceful development, mutual understanding, respect and cooperation between the two sides will not be smooth sailing."

Relations with China have grown increasing frosty since Tsai Ing-wen of the Democratic Progressive Party won the island's presidency in January. Beijing is highly suspicious of Tsai because her party is traditionally pro-independence, and has warned her against any attempt at a formal breakaway.

China's Taiwan Affairs Office announced it had suspended official contacts with Taipei after Tsai's government, which took office in May, failed publicly to accept the "one China" principle which governed relations under her predecessor.

Sha reiterated that "one China" was the basis for major progress in ties under Taiwan's previous Kuomintang government. He praised Mayor Ko for "openly expressing his understanding and respect" of it.

Taiwan has been self-ruling since splitting with the mainland in 1949 following a civil war but has never declared independence. Beijing still sees it as part of its territory awaiting reunification, by force if necessary.