QUITO -- Ecuadorans went to the polls on Sunday to elect a president, a vice president, 151 members of the National Assembly and five members of the Andean Parliament for a four-year term.

Polling stations opened at 7 am local time (1300 GMT) for more than 13.7 million voters and is scheduled to close at 5 pm (2200 GMT).

Preliminary results of the presidential race are expected later in the night. Under Ecuador's constitution, a presidential candidate who secures more than 50 percent of the vote in the first round or at least 40 percent with a lead of more than 10 percentage points over the runner-up wins the presidency outright. If no candidate meets these criteria, the top two candidates proceed to a runoff.

The Ecuadorian government has deployed about 100,000 military and police personnel for security. Nearly 1,000 domestic and international observers are set to monitor the process to ensure transparency.