Military police surrounded Venezuela's embassy in Brazil on Wednesday as rival supporters of Venezuelan opposition leader Juan Guaido and President Nicolas Maduro faced off inside in a struggle for control of the diplomatic compound.Embassy officials opened the doors to Guaido's appointed ambassador Teresa Belandria after recognizing the opposition leader as president, the envoy said in a statement.It was not immediately clear which side was in control of the embassy.The last Maduro-appointed ambassador to Brazil was withdrawn in 2016. Belandria said officials inside the embassy delivered "voluntarily the diplomatic headquarters to the legitimately accredited representation in Brazil" early on Wednesday."Upon entering the headquarters, we could verify that a group of officials was living in the official residence," Belandria said."We request all accredited officials at the embassy and in the 7 Venezuelan consulates, adopt this same decision."Freddy Mergote, a senior embassy official loyal to Maduro, said "strangers to our facilities are entering and are violating the Venezuelan territory," according to a voice recording sent to Brazil's left-wing Workers Party (PT) and shared with AFP. "We need help, we need the immediate activation of all social movements and political parties," Mergote said.Supporters of the Venezuelan president yelled "Viva Maduro." Venezuelan Foreign Minister Jorge Arreaza condemned what he described as an invasion of the embassy."We hold the Government of Brazil responsible for the safety of our staff and facilities," Arreaza tweeted."It is a delicate situation," said Paulo Pimenta, a member of PT, in a voice recording sent to AFP via WhatsApp. Pimenta said he was among 10 Brazilians to enter the embassy in the morning.The stand-off could not come at a worse time for Brazil's President Jair Bolsonaro, who is hosting the BRICS summit a short distance from the Venezuelan embassy.Brazil is among dozens of countries to recognize Guaido as Venezuela's legitimate leader, but BRICS titans China and Russia back Maduro. Bolsonaro is due to meet with his Chinese counterpart Xi Jinping at the foreign ministry Wednesday morning. Bolsonaro - an ardent admirer of US President Donald Trump with whom he shares a contempt for multilateralism and left-wing ideology - is under pressure from Brazil's powerful beef, farming and mining sectors to stay on good terms with China, the Latin American country's biggest trade partner.The BRICS summit will be the first time Bolsonaro, notoriously awkward at public events, has hosted a major international gathering since he took office in January.