UK implements new sanctions on Iran for supplying Russia with drones; Ukrainians prepare for hours-long power outages. This live blog is now closed

• At a glance: what we know on day 239 of the invasion

Oleh Synyehubov, governor of Kharkiv, has posted a status update for Thursday which says that yesterday two people died and four more were injured when “a car with employees of the state emergency service was blown up by a mine” in the Izium district.

He also said “a 78-year-old resident of Izium district was hospitalised with injuries during the day”.

It is Martin Belam taking over the live blog in London. You can contact me at martin.belam@theguardian.com

It likely indicates that the Russian authorities are seriously considering a major withdrawal of their forces from the area west of the Dnipro river.

A key challenge of any Russian withdrawal operation would be extracting troops and their equipment across the 1000m wide river in good order.

Russian president says four Ukrainian regions occupied by Russia will be put under martial law

• What we know on day 238 of the invasion

If you look hard enough, you’ll spot faded yellow signs proclaiming “fallout shelter” around New York City. They are remnants of a cold war programme that signalled spaces within ordinary buildings – from schools to banks to the Brooklyn Bridge – with adequate supplies and walls thick enough for riding out a nuclear blast safely.

Many of these windowless shelters housed little more than rats and sewage before the practice was terminated in 1979. In 2017, the city’s department of education ordered the “misleading” signs removed from its buildings, but many others remain – vestiges of nuclear fears that never materialised.