The recount in the Mexican presidential election has seen first one candidate and then the other take the upper hand.
Leftist anti-poverty campaigner Andres Manuel Lopez Obrador was ahead all day but then saw his lead cut back to a sliver yesterday.
Supporters of his rival, conservative former energy minister Felipe Calderon, began celebrating at the ruling National Action Party offices around midnight (5am Irish time) as he appeared to be rapidly gaining ground as results came in from north and west Mexico, his strongholds.
But officials said it was still too close to declare a winner.
With 95 per cent of polling stations reporting results of their recounted ballots, Mr Lopez Obrador, a former mayor of Mexico City, led pro-US free trade advocate Mr Calderon by just 0.57 percentage points.
Mr Calderon was judged to have won a preliminary count earlier this week by 0.6 percentage points, but Mr Lopez Obrador cried foul ,and protests broke out in the capital amid claims he was the victim of fraud.
Mr Lopez Obrador warned of trouble if the recount was not handled properly. "The stability of the country is at stake."
Mexico's stock market plunged 4 per cent and its peso fell against the dollar because of the political tension.
The Harvard-educated Mr Calderon is a pro-business lawyer and would be an ally of the United States in Latin America. Mr Lopez Obrador has promised to renegotiate a North American trade pact to block cheap US corn and beans entering Mexico as of 2008.