China's ambassador in South Africa Lin Songtian is set to leave Pretoria more than a year before the end of his term for what is rumoured to be a promotion by Beijing.The embassy has refused to comment on the move, but spokesperson Du Ping said a statement will be issued soon."It is good news for him," one official said.The latest press release by the embassy on Tuesday - to declare China's solidarity with South Africa as an increasing number of Covid-19 cases surfaced here - was unusually issued by Du and not under ambassador Lin's name. That might suggest that officially he might already be out of his position.Lin arrived in South Africa in 2017 and has built a reputation as one of the most media-friendly and outspoken Chinese ambassadors to South Africa to date. He has also, unusually, taken to publicly advising the South African government on issues like the economy and crime prevention.Six months ago, he opened a Twitter account, an unusual step for a Chinese ambassador, with much of his strongly-worded tweets directed at the United States on issues like the Hong Kong protests or the treatment of Chinese Muslims in Xinjiang.Twitter is not accessible in China.His tweets in recent weeks caused great controversy in the US.According to the China Africa Project newsletter published on Wednesday, Lin has persisted in amplifying Beijing's view that the Covid-19 virus didn't originate in Wuhan or China - something he also aired at a press conference in Pretoria, just as the first cases were reported in South Africa.His Covid-19 tweets were widely reported by conservative US media outlets, and Lin followed this up by tweeting: "We are ready to help the US people if requested."US saw it as a provocationThis was interpreted by the US as a provocation, according to the newsletter's authors, "because any offer of government-to-government assistance between the US and China would not typically be channeled through a Chinese ambassador in South Africa, and much less on Twitter". There is some speculation that his move is related to his tweets. Some South African officials, however, said China was withdrawing Lin temporarily due to the length of time South Africa was taking to appoint a new ambassador to Beijing after Dolana Msimang's term ended last year.Former minister Siyabonga Cwele was earmarked for this strategically important position, but he was recently denied security clearance to serve as a diplomat. It is believed he will appeal this decision.WATCH | Coronavirus update: China's ambassador to SA briefs media on latest developments"South Africa has taken more than a year to replace our ambassador in China," a South African government official said."The Chinese are recalling theirs temporarily to demonstrate their unhappiness."Relations between China and South Africa are, however, strong on the surface, with the two countries having shown support to each other since the outbreak of Covid-19 in Wuhan, China.South Africa initially refused to restrict travel from China, but has since repatriated citizens from Wuhan, epicentre of the Covid-19 outbreak, and this week issued severe travel restrictions from China and seven other high-risk countries.