The gathering by ‘overseas’ CNRP members is set to be held in Atlanta, GA. on Saturday and Sunday.
Experts say women remain underrepresented in politics in Cambodia.
Hun Sen did not reportedly respond to Heidt’s comments regarding political reconciliation or the release of Sokha.
Hun Sen said that he would not allow Cambodia to become a “stage for conflict” or for “testing ideologies or arms”.
The World Bank has warned that Cambodia’s economy will face increased risks if the EU presses ahead with Cambodia’s expulsion from the scheme.
The CNRP was the country’s largest political party and the only party to win seats in parliament in the 2013 election.
A group of liberal lawmakers from Asean nations meeting in Singapore this week will focus on Cambodia and Myanmar’s human rights record.
Some 25,000 government officials, civil servants and members of the security forces took part in the annual event in Phnom Penh.
President Trump among dozens of world leaders at Arc de Triomphe to mark end of the first world war.
Incumbent Jim Costa, a seasoned politician, beat Elizabeth Heng 54.4 percent to 45.6 percent, according to the State’s primary results.
The appeal was made at a meeting of the Overseas Khmer Summit (OKS) in Washington, DC, attended by Cambodian-Americans from several US states.
President Trump’s Republican Party had held the balance of power in all three branches of government prior to the vote, which saw the Democrats win control of the House of Representatives.