Shafaq News/ Myanmar's military seized power on Monday in a coup against the government of Nobel laureate Aung San Suu Kyi, who was detained along with other leaders of her National League for Democracy (NLD) party in early morning raids.

The army said it had carried out the detentions in response to "election fraud", handing power to military chief Min Aung Hlaing and imposing a state of emergency for one year, according to a statement on a military-owned television station.

In a statement late Sunday, White House press secretary Jen Psaki said the United States is “alarmed” by the reports.

“The United States opposes any attempt to alter the outcome of recent elections or impede Myanmar’s democratic transition,” Psaki said, adding that the U.S. “will take action against those responsible if these steps are not reversed.”

Biden has been briefed on the situation by his national security adviser, Jake Sullivan, Psaki said.

The announcement follows several days of worsening political tensions and rising fears of a potential military coup, and comes hours before a new session of parliament was scheduled to begin.

The ruling National League for Democracy (NLD) spokesperson Myo Nyunt confirmed the detentions to CNN Monday. "State Counsellor Daw Aung San Suu Kyi and some other senior figures are being detained in (the capital city of) Naypyidaw," Myo Nyunt said. "The military seems to take control of the capital now."

Several senior leaders from large states in Myanmar, including the ministers of Shan State, Kayah State, and the NLD Ayeyarwady state spokesperson, were also detained in the raids, Myo Nyunt said.

On Monday morning, Myanmar's main news channels were suspended from the air and there were reports of significant internet disruption in the county. Soldiers could also be seen outside city hall in the country's commercial center Yangon.

Last week, a military spokesperson said it would not rule out a coup if the military's claims of alleged voter fraud into the November 2020 election were not investigated.

Suu Kyi's party the NLD claimed an overwhelming victory in the country's second democratic ballot since the end of direct military rule in 2011, taking 83% of the vote, which allowed the party to form a government. The military-backed Union Solidarity and Development Party won 33 out of a possible 476 seats, fewer than the party expected.

Myanmar's election commission on Thursday rejected claims of voter fraud, saying any errors, such as duplicated names on voter lists, were not enough to impact the result of the vote.

Reuters reported that Myanmar state media MRTV is having technical issues and is unable to broadcast, the network said.