Myanmar said Thursday President Barack Obama had congratulated the nation on holding "free and fair" election, as the government and army chief promised a smooth transition of power with Aung San Suu Kyi's party edging towards victory.
The country has been dominated by the military for half a century through direct junta rule and since 2011 by a quasi-civilian government run by its allies.
But Suu Kyi's National League for Democracy (NLD) is on the verge of tipping the balance of power after capturing more than 85 percent of seats declared so far from Sunday's election -- a huge stride in the party's long democracy struggle.
Obama "called President Thein Sein this morning to congratulate him and the government for successfully holding a historic free and fair general election," Myanmar's Information Minister Ye Htut said on his official Facebook page.
The American leader has thrown his weight behind Myanmar's reform process and its pro-democracy figurehead Suu Kyi, visiting the country twice since the end of outright military rule in 2011.
He has urged the country to tackle religious intolerance and promote full democracy. He has also highlighted the plight of the ethnic Rohingya Muslims, tens of thousands of whom were excluded from voting.
In his call, Obama told his counterpart to be "proud of the milestone election" and praised "the president's brave reforms", said YeHtut, a close Thein Sein aide.
There was no immediate confirmation of the call by the US State Department.
By Thursday morning the NLD had swept up 273 seats, 56 short of an outright majority. It is almost certain to smash through that marker, with more official results due to be released on Thursday.
In statements released via Facebook, Thein Sein and the powerful army Chief Min Aung Hlaing congratulated Suu Kyi's party, vowed to respect the poll result and work with the new government.
The army chief repeated his position to military top brass, vowing "co-operation with the new government during the post-election period," according to a statement posted on his Facebook page Thursday.
Suu Kyi on Wednesday called for national reconciliation talks with the army chief and Thein Sein, stressing the need for a peaceful transition.
Many NLD supporters remain deeply suspicious of the army and its parliamentary allies, who are notorious for political sleight of hand and crackdowns on democracy movements that have left hundreds dead and thousands jailed.
Suu Kyi's party won a 1990 election by a landslide only for the army to ignore the result and tighten its grip on power.
In an indication of the days and weeks of manoeuvring through Myanmar's treacly politics that lie ahead, NLD spokesman Nyan Win said the call for talks was "our first move... to help a smooth transfer of power."
- Ruling party battered –
While its political proxy, the USDP, faces annihilation at the polls, the army has its stake in future carved out under a constitution it wrote.
It is gifted 25 percent of all parliamentary seats, as well as control of Myanmar's security apparatus -- meaning it will retain immense practical powers as a counterpoint to the NLD's popular mandate.
Suu Kyi's own path to power is also blocked by the 2008 constitution that bars anyone with foreign children -- or husband -- from the presidency.
Her sons are British as was her late husband -- who died in Britain while she was under house arrest in Myanmar.
'Mother Suu', as she is affectionately known, has said a democratic government would not seek to punish historic abuses by the military and a large parliamentary majority would increase her leverage against the army bloc.
But ahead of elections she struck a defiant note, saying she would take a position "above the president" in the event of an NLD win.
Now her party is poised for power it is likely she will put forward a proxy for the role, a move which could set her on collision course with the army.
Shwe Mann, a former general who is also a parliamentary speaker, has been previously tipped as a compromise candidate for the top office.
He was also invited to talks with Suu Kyi despite being sidelined by the USDP and losing his seat in the election.
Under Myanmar's complicated political system President Thein Sein holds his role until March next year, leaving a months-long interregnum that observers fear could allow political problems to incubate.