Passengers heading to Armenia and Turkey amid fears Russia could soon close borders to men of fighting age

• Russia-Ukraine war – latest updates

Demand for seats on private jets has boomed in Moscow after Vladimir Putin ordered the first mobilisation since the second world war and wealthy Russians look for a way out of the country amid reports that authorities plan to close the borders to men of mobilisation age.

Passengers are said to be predominantly heading to Armenia, Turkey and Azerbaijan, which allow Russians visa-free entry. They are paying between £20,000 and £25,000 for a seat on a private plane, while the price to rent an eight-seater jet ranges from £80.000 to £140,000, which is many times more expensive than the normal fare.

Kremlin says it has made no decision on closing Russia’s borders as many flee after Moscow’s military call-up; ‘referendum’ voting enters final day

• See all our Ukraine coverage

Russia’s “referendums” in Ukraine, which could lead to Moscow annexing 15% of the country’s territory, were due to end on Tuesday. Voting in the eastern provinces of Luhansk, Donetsk, Kherson and Zaporizhzhia began on Friday and have been dismissed as a sham by western nations, which have pledged not to recognise the results.

The Kremlin said it had made no decision on closing Russia’s borders as the first mobilisation since the second world war prompted some to flee.

The Nord Stream 2 pipeline’s pressure collapsed mysteriously on Monday. Authorities in Germany are trying to establish what caused the sudden drop in pressure in the defunct pipeline, with a spokesperson for its operator saying it could have been a leak.

A Russian man has shot the leader of the local military draft committee in a Siberian town after telling him he would refuse to fight in Ukraine. Video showed the gunman, dressed in camouflage, firing at the official from point-blank range as other potential draftees for the Russian invasion fled the room.

Long queues of vehicles formed at the border crossing between Russia and Mongolia as people continue to flee the Kremlin’s mobilisation order. The head of a checkpoint in the town of Altanbulag said more than 3,000 Russians had entered Mongolia via the crossing since Wednesday.

Nato air forces are conducting drills over the Baltic Sea. Member states including the UK, Germany and Italy have taken part in the military training, both over water and on land, in an effort to boost eastern defences.

The Netherlands has increased its military support for Ukraine. The prime minister, Mark Rutte, also announced new sanctions in response to Russia’s mobilisation and referendums.

The US pledged to provide Ukraine with $457.5m in civilian security aid. The support was aimed at “saving lives” and “bolstering” Ukrainian law enforcement, said the secretary of state, Antony Blinken.

The Russian Orthodox Church head says Russian soldiers who die on the battlefield will have their sins absolved. Patriach Kirill, a close ally of President Vladimir Putin and a staunch supporter of the Ukraine invasion, said the “sacrifice washes away all sins”.

The UK announced 92 new sanctions in response to Russia’s “sham referendums” in Ukraine. The package of penalties target those behind the sham votes as well as oligarchs and board members.

Germany is debating whether it should grant asylum to Russian war refuseniks. The interior minister, Nancy Faeser, said the country was potentially prepared to give protection to deserters who face repercussions if they refused to fight, but each case would be decided on an individual basis amid security concerns.

The UN’s atomic energy watchdog says it is ready for talks about setting up a protection zone around the Zaporizhzhia nuclear power plant. The International Atomic Energy Agency head met the foreign ministers of Russia and Ukraine at the UN general assembly last week to discuss the possibility.

The US has warned of horrific consequences if Russia follows through with its thinly veiled threats to use nuclear weapons. Antony Blinken said any use of the weapons would have a “catastrophic” impact across the world.

Negotiators of a spending bill in the US Congress have agreed to include nearly $12bn in new military and economic aid to Ukraine, Reuters reported sources as saying on Monday. The funding – requested by the Biden administration – would include $4.5bn for defence capabilities and equipment for Ukraine and $4.5bn in direct support to the Kyiv government, the sources said.

Ukraine claims some Russian conscripts from the Kremlin’s mass mobilisation are being sent directly to the frontlines without training. Those included newly drafted personnel in Crimea as well as conscripts in the Luhansk region who have received draft summonses in recent days.

Volodymyr Zelenskiy has vowed to liberate the entire country as Russia presses on with its supposed referendum in occupied areas of Ukraine. The Ukrainian president said the country’s armed forces would throw out Russia’s forces and retaliate against “every strike of the aggressor”.

Hastily arranged polls in Russia-controlled regions have seen little campaigning, but there are reports of door-to-door searches and repression

• Russia-Ukraine war: latest updates

With minimal preparation, armed soldiers standing guard and the booms of war often audible in the distance, so-called referendums got under way on Friday in areas of Ukraine occupied by Russian troops.

Residents in Russian-controlled parts of Donetsk, Luhansk, Kherson and Zaporizhzhia regions were told to vote on proposals for the four areas to declare independence and then join Russia.