A massive convoy outside the Ukrainian capital has split up and fanned out into towns and forests near Kyiv, with artillery pieces raised into firing position in a potentially ominous movement of the Russian military, new satellite photos appeared to show.

The photos emerged amid more international efforts to isolate and sanction Russia, particularly after a deadly airstrike on a maternity hospital in the port city of Mariupol that Western and Ukrainian officials decried as a war crime.

The US and other nations were poised on Friday to announce the revocation of Russia’s “most favoured nation” trade status, which would allow tariffs to be imposed on Russian imports.

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A destroyed tank on a main road near Brovary, north of Kyiv (Felipe Dana/AP)

Unbowed by the sanctions, Russia kept up its bombardment of Mariupol while Kyiv braced for an onslaught, its mayor boasting that the capital had become practically a fortress protected by armed civilians.

Satellite imagery from Maxar Technologies showed that the 40-mile convoy of vehicles, tanks and artillery has broken up and been redeployed, the company said.

Armoured units were seen in towns near the Antonov airport north of the city. Some of the vehicles have moved into forests, Maxar reported, with towed howitzers nearby in position to open fire.

The convoy had massed outside the city early last week, but its advance appeared to stall as reports of food and fuel shortages circulated.

US officials said Ukrainian troops also targeted the convoy with anti-tank missiles.

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A long line of people and cars waiting by the damaged Irpin River bridge during the Russian invasion, in Irpin (Satellite image ©2022 Maxar Technologies/AP)

Russian forces were continuing their offensive toward Kyiv from the northwest and east, notably trying to break through Ukrainian defences from Kukhari, 56 miles to the northwest, through to Demidov, 25 miles north of Kyiv, the general staff of Ukraine’s armed forces said in a statement.

Meanwhile, Russian president Vladimir Putin has ordered that so-called volunteer fighters should be brought into Ukraine.

Defence minister Sergei Shoigu said Russia knew of “more than 16,000 applications” from countries in the Middle East, many of them from people who he said helped Russia against the so-called Islamic State group, according to a Kremlin transcript.

They want “to take part in what they consider a liberation movement”, Mr Shoigu said, on the side of Russia-backed separatist regions in eastern Ukraine.

Since 2015, Russian forces have backed Syrian president Bashar Assad against various groups opposed to his rule, including Islamic State.

Mr Putin told Mr Shoigu that Russia should help would-be volunteers to “move to the combat zone” and contrasted them with what he called foreign “mercenaries” fighting for Ukraine.

A US defence official said Russian forces moving toward Kyiv had advanced about three miles in the past 24 hours, with some elements as close as nine miles from the city.

The official gave no indication that the convoy had dispersed or otherwise repositioned in a significant way, saying some vehicles were seen moving off the road into the tree line in recent days.

In Mariupol, a southern seaport of 430,000, the situation was increasingly dire as civilians trapped inside the city scrounged for food and fuel.

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Destroyed Russian tanks are seen on a main road after battles near Brovary, north of Kyiv (Felipe Dana/AP)

More than 1,300 people have died in the 10-day siege of the city, according to deputy prime minister Iryna Vereshchuk.

Residents have no heat or phone service, and many have no electricity. Night-time temperatures are regularly below freezing, and daytime ones normally hover just above it. Bodies are being buried in mass graves. The streets are littered with burned-out cars, broken glass and splintered trees.

“They have a clear order to hold Mariupol hostage, to mock it, to constantly bomb and shell it,” Mr Zelensky said in his nightly video address to the nation.

Repeated attempts to send in food and medicine and evacuate civilians have been thwarted by Russian shelling, Ukrainian authorities said.

The number of refugees fleeing the country topped 2.3 million, and some 100,000 people have been evacuated during the past two days from seven cities under Russian blockade in the north and centre of the country, including the Kyiv suburbs, Mr Zelensky said.

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Firefighters help a woman from a building in Mariupol (Evgeniy Maloletka/AP)

He told Russian leaders that the invasion will backfire on them as their economy is strangled.

Western sanctions have already dealt a severe blow, causing the rouble to plunge, foreign businesses to flee and prices to rise sharply.

“You will definitely be prosecuted for complicity in war crimes,” Mr Zelensky said in a video address, warning that “you will be hated by Russian citizens”.

Mr Putin dismissed such talk, saying the country has endured sanctions before.

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A man in a street damaged by shelling in Mariupol (Evgeniy Maloletka/AP

″We will overcome them,” he said at a televised meeting of government officials. He did, however, acknowledge the sanctions create “certain challenges”.

In addition to those who have fled the country, millions have been driven from their homes inside Ukraine. Kyiv mayor Vitali Klitschko said about two million people, half the population of the metropolitan area, have left the capital.

“Every street, every house… is being fortified,” he said. “Even people who in their lives never intended to change their clothes, now they are in uniform with machine guns in their hands.”

Western officials said Russian forces have made little progress on the ground in recent days and are seeing heavier losses and stiffer Ukrainian resistance than Moscow apparently anticipated.

But Mr Putin’s forces have used air power and artillery to pummel Ukraine’s cities.