Obama on Friday terminated an emergency order that judged the policies of Myanmar's previous military government a threat to US national security.

"I have determined that the situation that gave rise to the national emergency ... has been significantly altered by {Myanmar's} substantial advances to promote democracy, including historic elections in November 2015," he said in a letter to the US House and Senate speakers.

The move comes amid improving ties between Washington and the Naypyidaw government as Myanmar, which is also known as Burma, transitions from a dictatorship to democracy.

The Southeast Asian nation has pursued political reforms over the past five years following four decades of military rule, which saw pro-democracy activist Aung San Suu Kyi freed from 15 years of house arrest to become its civilian leader.

Suu Kyi's National League for Democracy won a sweeping victory in last November's elections.

"While Burma faces significant challenges, including the consolidation of its democracy, the United States can, and intends to, use other means to support the government and people of Burma in their efforts to address these challenges," Obama's letter said.

Suu Kyi's visit helped ties

Obama had announced plans to lift the sanctions last month, when Suu Kyi visited the White House. She urged US companies to set up businesses in her country.

The US has already eased many economic sanctions, which prevented American firms investing and trading with Myanmar.

But Friday's announcement lifted restrictions on military-owned companies and officials and associates of the former ruling junta, while retaining restrictions on military-to-military assistance.

The order reinstates preferential tariffs that were suspended more than two decades ago amid human rights abuses by the ruling junta.

Some US politicians are worried whether Myanmar's transition will be permanent, and have introduced a law to give Washington greater flexibility in the easing of sanctions.

Last month, the US State Department said visa restrictions on military leaders would remain in place.

mm/bw (AFP, AP, Reuters)