Coronavirus has forced more top Israeli officials into isolation after the country's health minister, who has had frequent contact with Prime Minister Benjamin Netanyahu, tested positive, the health ministry said on Thursday.

Israeli Health Minister Yaakov Litzman and his wife, who also contracted the virus, are in isolation but said they feel well and are being treated, a ministry statement said.

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Shortly after the announcement, the prime minister's office said Netanyahu returned to self-quarantine because of his contact with Litzman.

Netanyahu had previously been in isolation after a top aide tested positive for the virus. Netanyahu has tested negative.

The Israeli daily Haaretz reported the head of Israel's Mossad spy agency and the National Security Council were asked to self-quarantine because of their interactions with Litzman.

The health ministry's director and Litzman's staff also self-quarantined, and the ministry said requests to enter isolation will be sent to those who came in contact with the minister in the past two weeks.

Israel has gone into near-lockdown to try to contain the outbreak. The country has reported more than 6,200 confirmed cases and 31 people have died from COVID-19, the illness caused by the virus.

Israel's large, insular ultra-Orthodox community, of which Litzman is a member, has been particularly hit hard by infections. In the early phases of the outbreak, some rabbis pushed back or ignored government-mandated movement restrictions, but resistance appears to have diminished.

On Wednesday, Netanyahu ordered a police cordon around the largely ultra-Orthodox city of Bnei Brak, east of Tel Aviv, to limit movement to and from the city. Bnei Brak has the second-highest number of coronavirus cases in Israel.

For most people, the coronavirus causes mild or moderate symptoms, such as fever and cough. But for others, especially older adults and people with existing health problems, the virus can cause severe symptoms like pneumonia or death.