LONDON — British Prime Minister Boris Johnson is self-isolating after coming into contact with someone who tested positive for COVID-19, a fresh setback after infighting among his top advisers plunged Downing Street into chaos last week.

Johnson, who was admitted to intensive care in a London hospital earlier this year with the novel coronavirus, is well and does not have any symptoms, a spokesman for the prime minister said on Sunday.

“He will carry on working from Downing Street, including on leading the government’s response to the coronavirus pandemic,” the spokesman said.

“The prime minister will follow the rules and is self-isolating.”

Johnson met lawmakers in Downing Street on Thursday, including Lee Anderson, a Conservative Party member who subsequently developed COVID-19 symptoms and tested positive.

The British leader had been hoping to seize back the initiative after last week’s drama in Downing Street.

Johnson’s office said on Friday that Dominic Cummings, the prime minister’s most powerful adviser and a fellow veteran of the Brexit referendum, would stop working for him next month.

Weekend newspapers were full of reports of bitter rows between rival factions in Downing Street that painted a picture of a government in chaos.

In an attempt to show he was not letting the upheaval distract him, his office said Johnson would make a string of “critical announcements” over the next two weeks on issues from green policy to a return to regional COVID-19 rules from Dec. 2.

Johnson has come under pressure from within his party not to extend the economically damaging, four-week coronavirus lockdown that he ordered for England this month.

Downing Street said the prime minister would remain firm in the finale of talks with the European Union over a post-Brexit trade deal and reiterated that he was ready to end Britain’s transition period on Dec. 31 without a trade deal if necessary.

Johnson will agree a one-year public spending plan with his finance minister, Rishi Sunak - to be announced on Nov. 25 - and he will publish this week a plan setting out steps for a “green industrial revolution” to boost green jobs as Britain aims for net zero carbon emissions by 2050, the statement said.