Pathet Lao Announce Vientiane Take‐Over
300,000 Laotians gather in Vientiane to mark Communist-led Pathet Lao takeover of city, repts monitored from Vientiane radio and Pathet Lao news agency broadcasts; takeover began when Pathet Lao troops and tanks rolled through Savannakhet, May 20; crowd reptdly is addressed by 'uprising com' chmn Thao Moun; Premier Souvanna Phouma's and King Savang Vatthana's status unclear; Pathet Lao reptdly has said it continues to respect and recognize Phouma as head of Govt and Vatthana as head of state; Vientiane radio earlier announces takeover of Luang Prabang, 130 mi northwest of Vientiane; long-expected takeover was heralded when Laotians authorities sealed country's borders, cut all internatl telecommunications and closed airports for 24 hrs; Nong Khai Prov (Thailand) Gov Kampol Klinsukol ordered entire frontier bordering Laos sealed for at least 5 days in expectation of Vientiane celebrations; border incidents have increased in recent days and diplomats of both countries have been expelled as bitterness between Govts grew (M)