HANOI, Jan. 28 (Reuters) - Vietnam’s health ministry on Thursday confirmed its first two locally transmitted COVID-19 cases in nearly two months, just weeks before the country’s Lunar New Year holiday period, when big gatherings indoors are expected.

Though a tiny number compared with new coronavirus infections in many countries, the two cases are a jolt for Vietnam. Thanks to strict quarantine, testing and tracing measures, it has reported only 1,551 cases and 35 COVID-19 deaths before Thursday, earning it a top three spot in a survey of how well countries have handled the pandemic.

On Thursday Vietnam’s health ministry ordered provinces and state agencies to tighten screening and controls.

Contact tracing efforts were launched in two northern provinces Hai Duong and Quang Ninh, where the two new infections were detected - one of which was linked to the new UK variant of the virus - and a village in Hai Duong was locked down, according to state media. The UK variant has been determined to be much more easily transmissible.

“We have to make all efforts to locate the infected areas within 10 days to put down the outbreak,” Vu Duc Dam, head of the national COVID-19 task force said in a health ministry statement.

In awkward timing for the country’s government, the two new cases also came as the ruling Communist Party gathers in Hanoi for its five-yearly congress to pick new leadership, with 1,600 delegates from across Vietnam in attendance.

On Thursday Vietnam’s Prime Minister Nguyen Xuan Phuc convened a meeting on the sidelines of the congress with the national COVID-19 taskforce to discuss the new outbreak. The wearing of face masks was also made compulsory at the congress venue for the first time since it kicked off on Monday.

The latest patients include a support staff worker at Van Don international airport who was responsible for taking infected passengers arriving from abroad to COVID-19 quarantine facilities.

The other case is a factory worker who came into contact with a Vietnamese national who later travelled to Japan and tested positive there for the new UK variant of the virus, which has been determined to be much more easily transmissible.

“The airport staff worker has been to several public places, including hospital,” the health ministry said in its statement.

“For the factory worker case, considering its involvement with the UK variant, contact tracing has to be done as fast as possible but in a very cautious and careful manner.”

Vietnam’s stringent anti-coronavirus steps helped quickly contain its early coronavirus outbreaks, allowing it to resume its economic activities earlier than much of Asia.

A first wave of infections was crushed in April, and the country went nearly 100 days without local transmission until the reappearance of the virus in the central city of Danang in July. Further cases were detected in business hub Ho Chi Minh City in early December.

It has effectively closed its borders to combat the coronavirus and has suspended inbound flights from countries with new COVID-19 variants, initially Britain and South Africa.