The high-profile visit follows trips by First Lady Michelle Obama in 2015 and President Barack Obama in 2012.
On Sunday, Sam Rainsy also took part in a video conference, addressing supporters in Kampong Cham province, urging unity and support for the party.
Tep Nytha was reinstated to the NEC as secretary-general following lengthy discussions among nine appointed members of the committee at the Ministry of Interior on Friday.
A record number of candidates are running in Taiwan's legislative elections on Saturday. Among them is one candidate, born in Cambodia.
This week’s message underscores the sensitive nature of Cambodian politics, where insults are taken very personally and defamation is a criminal offense.
With the country looking toward national elections again in 2018, the CPP has been undertaking internal changes to help it connect with voters.
លោកប្រធានាធិបតីស.រ.អា.បារ៉ាក់អូបាម៉ាដែលកំពុងកសាងកេរតំណែល បានថ្លែងសុន្ទរកថាអំពីស្ថានភាពប្រទេសជាតិ State of the Uinion លើកទី៧របស់លោកនៅយប់ថ្ងៃអង្គារ។
Hun Sen already has an official account, as does his political rival, Sam Rainsy, head of the Cambodia National Rescue Party.
In a 49-page strategy paper distributed at the meeting, it said the party will focus on establishing local networks across the country to bolster support and prepare for elections.
With more elections just around the corner, Cambodia’s leaders will have to shift their focus to the youth, a powerful new force in a rapidly changing country, political analysts say.
Hun Sen made the comment at the annual ceremony to mark Jan. 7, 1979, when Vietnamese-backed forces ousted the Khmer Rouge from Phnom Penh.
Prime Minister Hun Sen will join other Asean leaders for a special meeting with US President Barack Obama in California next month.