The Southeast Asian country reported 11,397 new cases and 101 deaths on Sunday, taking the total number of infections to 403,386 and cumulative fatalities to 3,341, according to the Centre for the COVID-19 Situation Administration (CCSA).
From Tuesday, shopping malls will be closed, while travel restrictions and a curfew between 9 p.m. and 4 a.m. will be imposed in the provinces of Ayutthaya, Chonburi and Chachoengsao, reports Xinhua news agency.
These measures will last for 14 days, according to a royal gazette announcement.
The capital Bangkok and nine provinces have been put under such partial lockdown from July 12 onwards and for at least 14 days, as the country is grappling with its worst wave of the outbreak.
Thailand has been trying to secure more vaccines as it vows to inoculate about 70 per cent of its nearly 70-million population by the end of the year.
Till date, the country has administered more than 14.2 million doses of vaccine, with less than 5 percent of the total population having been fully vaccinated, according to the CCSA.
Thailand planned to buy 50 million more doses of Pfizer vaccine from the US, in addition to an order of 20 million doses that has been placed with delivery scheduled between October and December, Deputy Prime Minister and Public Health Minister Anutin Charnvirakul told reporters on Sunday.
The new purchase plan has yet to be approved by the cabinet of ministers, according to Anutin.