YANGON (Kyodo) -- Myanmar's ruling party led by the country's leader Aung San Suu Kyi lost a constituency it previously held, to the military-backed opposition party, in by-elections held over the weekend, preliminary results showed Sunday.
Some officials of the ruling National League for Democracy are taking the by-election result as a warning against complacency ahead of the next general election in 2020.
The by-elections were held Saturday to fill five seats in the national parliament -- four in the lower house and one in the upper house.
The NLD's candidate for the upper house seat in Kachin State, an ethnic minority area bordering China, was defeated by his rival from the Union Solidarity and Development Party, the former ruling party.
As for the four lower-house seats, the NLD won three of them and an ethnic minority party in Shan State the other. Both parties had previously held the seats.
Simultaneously, by-elections were held for eight seats in state and regional assemblies. The NLD lost three out of seven it previously held to the USDP and an ethnic minority party, according to the results.
The country's election commission so has yet to release official results.
The by-elections are seen as an indicator of whether the NLD can again achieve a landslide victory in the next general election in 2020.
Although Suu Kyi is still widely popular throughout the country, there is widespread discontent at the slow pace of reforms in Myanmar since the NLD came to power in 2015.
Speaking to local reporters in the country's second-largest city Mandalay, NLD Vice Chairman Zaw Myint Maung said the results are a wake-up call for the party to put more effort into preparing for the 2020 elections.
"This is a lesson for us. We will learn from our losses this time and prepare for 2020," said Zaw, who also serves as the chief minister of Mandalay Region.
Myo Nyunt, a party central executive committee member and NLD spokesman, however, said although he sees the by-election results as a significant lesson for the party, it cannot be taken as a barometer for the 2020 contest because the voter turnout was much lower.
The turnout in Saturday's polls was only around 30 to 40 percent, a figure similar to the by-elections held last year, according to poll observers.
The outcome of the by-elections does not affect the balance of power within the parliament, where the NLD enjoys a large majority.