The Cambodian Health Ministry said all 628 people who were part of the visit have tested negative so far and it urged everyone who had contact with the Hungarian delegation to be tested and to quarantine for two weeks.
Hungarian Foreign Minister Peter Szijjarto had tested negative before leaving Hungary on Monday and tested negative in Cambodia as well, the Cambodian foreign ministry said.
On Tuesday, he paid a courtesy call on Hun Sen and held separate meetings with Foreign Minister Prak Sokhonn and the ministers of commerce and agriculture. Photos showed Szijjarto did not wear a mask when meeting with Hun Sen and Prak Sokhonn, though other Hungarians did. Prak Sokhonn did not wear a mask and greeted his visitor with a handshake.
Later that day, Szijjarto traveled to Thailand, where he tested positive on arrival. He was placed in quarantine before leaving for Hungary on Wednesday, and all his meetings in Bangkok were canceled. The rest of his entourage tested negative.
Hun Sen, 68, has ruled Cambodia for 35 years.
Cambodia has reported about 300 cases of coronavirus in total and reopened schools on Monday for the first time since March, with class sizes and hours limited by anti-virus precautions.