WASHINGTON, March 29 (CNA) - The US is immediately suspending all engagement with Myanmar under a 2013 trade and investment agreement until the return of a democratically elected government, US trade representative Katherine Tai said on Monday (Mar 29).

Saturday was the bloodiest day of protests in Myanmar since the Feb 1 military coup with 114 people killed. Five more were killed on Monday when thousands took to the streets again in opposition to the military returning to power after a decade.

Tai said in a statement that Myanmar security forces' killing of peaceful protesters, students, workers and labour leaders and children "has shocked the conscience of the international community".

"These actions are a direct assault on the country’s transition to democracy and the efforts of the Burmese people to achieve a peaceful and prosperous future," said Tai, who was sworn into office on Mar 18.

In addition to suspending work on the 2013 framework agreement, Tai said the USTR would consider Myanmar's situation as it works with the US Congress on reauthorising the Generalised System of Preferences programme, which reduces US tariffs and provides other special trade access for some developing countries.

Participation requires countries to maintain certain worker rights protections, and Tai said reports that Myanmar's military leaders have targeted trade unions and workers for their role in pro-democracy protests raise serious concerns.