MEXICO CITY, July 16 (Reuters) - Some 92 Cuban doctors and nurses who lent a hand to Mexico during the coronavirus pandemic in recent months have been flown home, Mexico"s foreign ministry said on Friday. Communist-led Cuba has exported doctors as a central part of its diplomatic efforts since its 1959 revolution. Its doctors were in the front lines in the fight against cholera in Haiti and ebola in West Africa in the 2010s. In Mexico, the doctors worked mostly in the eastern part of the capital Mexico City, which is now experiencing another flare-up in coronavirus cases. "Mexico ... returned to Havana, Cuba, 92 doctors and nurses who in recent months provided their services in our country to help address the COVID-19 pandemic," the foreign ministry said in a statement. "The support of Cuban doctors is proof of the historical friendship that Mexico has with Cuba." Cuba"s critics in the United States say the doctors work under exploitative conditions and are used to support the Communist government"s allies. But Mexican officials have been grateful for the help at a time when their healthcare system was stretched to a breaking point. In January, Mexican President Andres Manuel Lopez Obrador thanked the Cuban medical staff for their help in fighting the pandemic. It is not clear why the doctors left as Mexican hospitals are under increased pressure amid another wave of coronavirus cases. This week daily confirmed coronavirus cases spiked to their highest level since early February. It was also not immediately clear if any Cuban medical practitioners remained in Mexico.