HANOI: The United States has "deep concerns" about the military coup in Myanmar and called on Southeast Asian nations to take action to end violence and restore democracy in the country, Secretary of State Antony Blinken said on Wednesday.

The Association of Southeast Nations (ASEAN) has been leading the main diplomatic effort on member country Myanmar since a Feb. 1 coup plunged it into turmoil.

During a video conference with ASEAN foreign ministers on Wednesday, Blinken urged ASEAN to take "immediate action" on a five-point consensus, agreed upon in April, to appoint a special envoy to Myanmar, State Department spokesperson Ned Price said in a statement.

Myanmar has descended into chaos after the coup, with hundreds of protesters killed by security forces and thousands jailed amid paralysing strikes and spreading conflict in border regions.

Blinken asked for the release of all those "unjustly detained" in the country, and the restoration of Myanmar's democratic transition, Price said.

Blinken also emphasised the U.S. rejection of China's "unlawful maritime claims" in the South China Sea and said Washington "stands with Southeast Asian claimants in the face of (Chinese) coercion", Price said.