FSB says it has detained people carrying out reconnaissance near the homes of Margarita Simonyan and Ksenia Sobchak

• What we know on day 507 of the invasion

Russian president Vladimir Putin held a phone call with South African president Cyril Ramaphosa in which the two leaders discussed the Black Sea grain deal and an African peace initiative on Ukraine, the Kremlin said on Saturday.

On the grain deal, which expires on Monday, Putin reiterated to Ramaphosa that commitments to remove obstacles to Russian food and fertiliser exports had not yet been fulfilled, the Kremlin said.

Zelenskiy says Russia doing everything it can to stop Ukrainian troop advance; Putin says he tried and failed to have Prigozhin replaced as Wagner leader in Ukraine

• See all our Russia-Ukraine war coverage

Volodymyr Zelenskiy has said Ukrainians must understand that Russia is deploying all possible resources to stop Kyiv’s forces from advancing in the east and south of Ukraine. It comes after reports of the counteroffensive advancing slowly. The Ukrainian president said on Friday: “We must all understand very clearly, as clearly as possible, that Russian forces in our southern and eastern lands are doing everything they can in order to stop our soldiers.”

The head of the Ukrainian president’s office said battles were difficult but that western allies were not putting pressure on Kyiv to advance faster. Andriy Yermak said: “Today it’s advancing not so quickly. If we are going to see that something is going wrong, we’ll say so. No one is going to embellish.”

Vladimir Putin has said he sought and failed to have Yevgeny Prigozhin replaced as the leader of Wagner’s fighters in Ukraine. Putin’s version of events, which appeared in an interview with the Kommersant newspaper, was a surprise admission that the Russian president was still negotiating a takeover of the Wagner mercenary group.

Boris Johnson has criticised Nato’s “mealy mouthed procrastination” and called for a timetable to be drawn up for Ukraine to join, after this week’s difficult summit in Lithuania. Writing in the Daily Mail, the former British prime minister said it was “no wonder” that Volodymyr Zelenskiy “found it hard” to conceal his frustration at the joint declaration released on Tuesday that stopped short of outlining a roadmap to Nato membership.

Vladimir Putin has agreed to extend the Black Sea grain deal, which expires next week, according to the Turkish president. Recep Tayyip Erdoğan said on Friday that he had spoken with his Russian counterpart about the crucial deal allowing for the export of Ukrainian grain to ease a global food crisis. Moscow played down Erdoğan’s comments, saying an agreement had not yet been reached.

A Kyiv court has ordered pre-trial detention for a senior cleric of a branch of the Ukrainian Orthodox Church with historic links to Moscow on suspicion of sympathising with Russia’s invasion of Ukraine. Ukrainian news reports said a Kyiv district court set bail at more than 33 million hryvnias (about $900,000). The church denies the allegations and says it severed all ties with Moscow last year. Metropolitan Pavlo had been under house arrest since April on suspicion of inflaming religious hatred and justifying the Russian invasion of Ukraine.

An alleged Russian intelligence officer has pleaded not guilty to US charges of smuggling American-origin electronics and ammunition to Russia to help its war against Ukraine. Vadim Konoschenok, who was extradited on Thursday from Estonia, entered the plea in federal court in Brooklyn, New York, on Friday. Magistrate judge Ramon Reyes ordered Konoschenok, 48, be detained pending trial, after prosecutors called him a flight risk.

Russian air defence systems shot down two UK-supplied Storm Shadow missiles that Ukraine had fired at Melitopol and Berdiansk on Thursday, the Russian-imposed leader of occupied Zaporizhzhia, Yevhen Balitsky, has claimed.

Mercenary fighters from Russia’s Wagner group are training Belarusian soldiers in Belarus, the country’s defence ministry has said. “[Wagner] fighters acted as instructors in a number of military disciplines,” it said on Friday.

A Ukrainian court has jailed a man for 10 years after finding him guilty of plotting with Russia to blow up transport infrastructure to disrupt foreign arms supplies. Ukraine’s domestic security agency said it detained the man in February before he had been able to carry out his mission.

Volodymyr Zelenskiy held a meeting with Ukraine’s intelligence chief and said on Telegram that according to intelligence data, there was no threat of invasion from Belarus.

Russia has accused the west of sponsoring “nuclear terrorism” after authorities said a Ukrainian drone struck the western Russian town of Kurchatov, where a nuclear power station similar to the Chornobyl plant is located. Roman Starovoit, the Kursk oblast governor, said on Telegram that no residents were injured. “Critical facilities were not damaged as a result of the drone crash and its subsequent detonation.”

Andriy Yermak says West are not pressuring Ukraine to go faster ; Kremlin denies Turkish claim deal will be renewed. This live blog is closed

• Putin says he tried but failed to oust Prigozhin after Wagner mutiny

Oleg Kiper, governor of Odesa region, reports on Telegram this morning that several settlements within the region are currently without power. However, he states this is due to adverse weather conditions overnight, rather than action by Russian Federation forces, who struck the port city earlier this week with drones causing a fire in a grain facility.

In Russia the Interfax news agency reports that three Ukrainian drones (UAVs) were intercepted in the Voronezh region.

Biden doesn’t see ‘any real prospect’ Putin will use nuclear weapons; three people killed in Russian shelling

• See all our Russia-Ukraine war coverage

US president plays down worries during Finland visit when asked about whether Russian president could escalate action in Ukraine. This live blog is now closed

• Biden ‘serious’ on prisoner swap for US reporter Evan Gershkovich

Pavlo Kyrylenko, Ukraine’s governor of Donetsk, has posted an operational update listing a number of settlements that suffered bombardment and “massive artillery shelling” damaging houses and residential buildings. He stated that “In total, the Russians wounded 8 residents of Donetsk region in one day.”

The claims have not been independently verified. Donetsk is one of the partially occupied regions of Ukraine which the Russian Federation claims to have annexed.

In the Darnytskyi district of Kyiv, during a night attack, a fragment of a downed drone hit the 25th floor of a building, destroying one of the apartments.

The man whose apartment was hit was at home – he was wounded by shrapnel, he was given help, now he is in a stable condition, reports our correspondent, who managed to talk to him.