National COVID-19 task force spokesperson Wiku Adisasmito said new cases in Sumatra had risen “significantly” by 27.22 percent this month from January, while at the same time cases in Java had decreased by 11.06 percent.

“In February and March this year, no provinces in Sumatra were among the top-10 largest contributors to COVID-19 nationwide cases. But in May, five provinces in Sumatra made the list,” Wiku told a press briefing on Thursday.

The five provinces were Riau, West Sumatra, Bangka Belitung Islands, Riau Islands and South Sumatra.

The same trend was also seen in the number of deaths in Sumatra in the same period, with an increase of 17.18 percent, while deaths in Java decreased by 16.07 percent.

Read also: Indonesian Muslims celebrate second Idul Fitri under pandemic shadow

The task force data also showed that all but one of the country’s 34 provinces were home to regions with medium risk of COVID-19 transmission, orange zones in the color-coded risk-based system.

“COVID-19 is not a problem exclusive to Java as we found an increase in the number of cases outside Java, which could also occur in [less crowded] regions away from the hustle and bustle,” Wiku said.

“Bear in mind that if there is no anticipation [to contain the spread of the virus and reduce people’s mobility], COVID-19 virus can reach your regions with zero recorded cases.”

Wiku said the government had asked local administrations to immediately take measures to respond to the situation, including by thoroughly checking travel and health documents of people entering and leaving their regions for inbound and outbound Idul Fitri mudik (exodus) travel.

The pandemic has forced the government to ban mudik for the second consecutive year, with the exception of life-or-death family emergencies and work-related trips -- all eligible travelers of which must carry permission letters from their supervisors or respective local administrations.

Read also: Bribes, lies and black sticky rice: Indonesians outsmart 'mudik' ban

The Transportation Ministry’s director general for land transportation, Budi Setiyadi, said the government would increase the intensity of random testing, especially on travelers using land transportation before they entered Greater Jakarta.

“We are anticipating travelers coming back to Jakarta. These are some changes that are required to protect Jakarta,” Budi told a press conference on Thursday.

Transportation Ministry spokesperson Adita Irawati said antigen or GeNose breathalyzer testing was mandatory for every traveler departing from Sumatra’s airports and seaports.

Last year, Indonesia saw a spike in infections across the country following Idul Fitri, particularly after thousands of people violated the mudik ban. In the weeks following Idul Fitri, nationwide cases rose around 68 to 93 percent, while fatalities climbed 28 to 66 percent.

Indonesia recorded on Thursday 3,448 new cases, bringing the total tally to 1.73 million cases, with more than 47,000 deaths since the first two cases were reported in the country over a year ago.