Updated

Conservative candidate Guillermo Lasso says his campaign for the presidency of Ecuador detected irregularities at almost 2,000 polling tables where his opponent handily won Sunday's runoff.

It's the strongest argument yet backing up his claims that ruling-party candidate Lenin Moreno won the election through fraud.

The Lasso campaign told a press conference Wednesday said that it detected irregularities such as missing signatures and inverted results in 1,795 voting acts it compared with official results.

Those polling places together represent about 600,000 votes, more than double Moreno's margin of victory. It presented three such examples and said it would dispute results at the voting centers, some of which Moreno won by a 4-to-1 margin.

Electoral authorities said if necessary they will recount votes at polling centers where results are formally challenged.