"Foreign Minister Delcy Rodriguez was attacked by the Argentine government police, she sustained a serious injury and probably a fracture of clavicle," Maduro said on Wednesday, as quoted by the Noticias24 media outlet.
He said that the minister was "thrown to the floor" by an officer of the Argentine Foreign Ministry’s security service.
"We lodged a vigorous and absolute protest against the coward behavior of the Argentine government toward this dignified young woman, who represents the voice of the Simon Bolivar’s people," Maduro said.
Mercosur presidency for the second half of 2016 was supposed to be transferred to Venezuela, after Uruguay officially ended its chairmanship in July. However, there have been concerns over growing discord in Venezuela amid a political standoff between Maduro and the opposition-dominated parliament.
Venezuela was officially notified of having its membership in Mercosur suspended earlier in December.