Argentine opposition leader Massa leading in Buenos Aires primary

Sergio Massa (C), major of Buenos Aires' Tigre town, votes for primary elections at a polling station in a public school in Tigre August 11, 2013. REUTERS/Enrique Marcarian

BUENOS AIRES (Reuters) - Argentine opposition leader Sergio Massa was leading in the midterm primary Congressional election in the must-win province of Buenos Aires, the government said on Sunday, with 2 percent of the vote counted.

In the open nationwide primary, opposition parties are running against President Cristina Fernandez's FPV coalition.