TOKYO -- Shigeru Ishiba, a heavyweight lawmaker in Japan's ruling Liberal Democratic Party, on Monday attacked Prime Minister Shinzo Abe's handling of the coronavirus pandemic.

The 63-year-old, who has twice challenged Abe for the party leadership, told foreign media in Tokyo that the prime minister was slow to restrict travel from China, the original epicenter of the virus.

"Japan should have much earlier implemented stricter restrictions on people coming from China and other countries that had seen many infections," Ishiba said. "Not doing this has a very negative impact."

On Feb. 1, Japan banned non-Japanese travelers who had recently visited China's Hubei Province, where the outbreak started in the city of Wuhan. It later expanded the restriction to other provinces. On March 5, Abe said Japan would quarantine all visitors from China at hospitals or other designated facilities before granting them entry permits.

Ishiba pointed to Hokkaido, the northern Japanese island that recently lifted a state of emergency order, after suffering a high number of early infections. A man and his son there were confirmed to have been infected in February after the father returned from Wuhan on Jan. 30.

The former defense minister, who has been shut out of Abe's cabinet, said Japan should have taken lessons from Taiwan, which has had fewer cases than neighboring countries. On Feb. 7, the island said all passengers arriving there after transiting via China, Hong Kong and Macao would have to quarantine themselves for 14 days.

"Japan should have looked at Taiwan, which has good information on the situation on the mainland," Ishiba said. "Taiwan acted very quickly."

Ishiba's news conference came a day after residents of Tokyo were requested to stay home over the weekend, due to a spike in the number of cases in Japan's capital. The city has recorded more than 40 infections on each of the past four days.

Speculation is now swirling that Abe may ask people across the country to refrain from going out for a few weeks to contain the virus -- a kind of voluntary lockdown, as the law does not allow the government to order people to stay at home.

"We may see restrictions on movement," Ishiba said. "It is crucial that the government fully explains to the public under what conditions it will come to an end, and what support it will provide."

He also criticized the government for allowing passengers that disembarked from the Diamond Princess cruise ship to return home by public transport. And while he said that Abe was correct to request that schools nationwide be shut, he chided the prime minister over what he sees as poor communication.

"At [Abe's] news conference to announce the school closures, there was no message to working families or single-parent families on what measures would be taken to support them," Ishiba said. "The prime minister also indicated he didn't speak to local governments beforehand about his request."

Ishiba lost to Abe in both the 2012 and 2018 LDP leadership elections, but maintains grassroots support from party members.

In December, he topped a Nikkei opinion poll that asked who would be the most appropriate person to lead the next government. He was favored by 20%, beating rising star Shinjiro Koizumi at 17%, and Abe, who scored 15%.

Ishiba made it clear on Monday that he still has ambitions for the top job, but that the coronavirus was now the first priority.

"The most important thing now is how Japan and the rest of the world will contain the situation," Ishiba said. "Only then can we create a new Japan and a new world."