BUENOS AIRES, Sept 17 (Reuters) - Argentina"s government remained mired in uncertainty on Friday, with President Alberto Fernández yet to decide the fate of rebel ministers who tendered their resignations earlier in the week, sparking a political crisis. Amid frenzied speculation from political commentators and local media over ruptures in the ruling Peronist coalition, Fernández took part, as planned, in a virtual climate forum convened by U.S. President Joe Biden. Center-left President Fernandez has been fighting against a cabinet revolt from ministers allied with the hard-left wing of his party since a bruising defeat in a midterm primary election last Sunday put the government"s grip on Congress at risk. Divisive but powerful Vice President Cristina Fernandez de Kirchner on Thursday night lashed out at what she said were errors made by the government, sharpening tensions between the moderate faction around President Fernandez and her more militant supporters. The electoral blow left the party stuck between two paths: Deepening populist policies to ease conditions for hard-hit Argentines or a more moderate approach to lure back middle-class voters who rallied behind the conservative opposition. On Wednesday, several ministers, including the interior minister, tendered their resignations to Fernández, though he has yet to publicly accept or reject them. On Thursday night the president and Fernández de Kirchner both went on the offensive. In a public letter, she called for a shake-up of the ministries and slammed a shortfall in public spending. "I sincerely trust that with the same strength and conviction that he faced the pandemic, the President will not only relaunch his government, but will also sit down with his Minister of Economy to look at the budget numbers," she wrote. The president on Twitter said that he would be the one to determine the future of the government. "The administration of the government will continue to develop in the way that I deem appropriate. For that I was elected," he said.