Leftist Rafael Correa has edged closer to victory in Ecuador's presidential election, promising wide reforms.
Rafael Correa has a strong lead with more than half of votes in
With almost two-thirds of votes counted, Mr Correa had almost 63% of the vote while his conservative rival Alvaro Noboa polled about 38%.
Washington has congratulated Mr Correa, who opposes a free trade deal with the US, on his apparent victory.
Mr Noboa, a billionaire banana tycoon, has not yet accepted defeat, with full results due on Tuesday.
Ecuador has seen much political turmoil in recent years with seven presidents in the last decade.
The last three elected presidents were overthrown and only three since 1979 have succeeded in serving full terms.
Mr Correa, a 43-year-old economist, declared victory on Sunday evening and on Monday took a congratulatory phone call from US Ambassador Linda Jewell.
"Thank God, we have triumphed," Mr Correa told supporters in the capital Quito.
"We accept this victory with dignity and humility... We are just instruments of the power of the people."
Ambassador Jewell said in a statement that Washington hoped to work "in a productive manner" with a government led by Mr Correa.
Although the full official result has not yet been announced, Mr Correa has moved quickly to make policy announcements and appoint ministers.
He said he will try to rejoin the Organisation of Petroleum Exporting Countries (Opec) which Ecuador left in 1992.
He also named leftist economists Ricardo Patino and Alberto Acosta as his economy and energy ministers.
His rival, Mr Noboa, said he would wait until official results were announced before asking for a recount if necessary.
Alvaro Noboa has said he will ask for a recount if necessary
Before voting, he had gone down on his knees, Bible in hand, and asked God for support.
"Like Christ, all I want is to serve... so that the poor can have housing, health care, education, jobs," Associated Press news agency quoted him as saying.
Ecuador's richest man, Mr Noboa had campaigned promising to attract foreign investment to Ecuador. He frequently carried a Bible.
He had said he would build 300,000 new homes a year for Ecuador's poor.
Foreign debt promises
An economic aide to Mr Correa said he would not pay some of Ecuador's "illegitimate" foreign debt and would not sign a free trade agreement with the US, Reuters said.
While campaigning, Mr Correa said he wanted to renegotiate contracts with foreign oil companies.
However, one adviser to Mr Correa told the Reuters news agency on Monday that as president Mr Correa would be unlikely to nationalise Ecuador's energy industry.
Mr Correa is close to Venezuela's anti-American President Hugo Chavez and has called US President George W Bush a "dimwit".
He toned down his comparison to Mr Chavez after he lost the first round vote to Mr Noboa.
Both candidates had promised to create jobs and fight poverty and corruption. Both had also promised to double the monthly government payout poor Ecuadoreans receive.