Scanning the sky for incoming artillery fire has become a force of habit for Ukrainian beetroot-seller Svetlana Kumurzhi, who dived under her wooden stall in government-held Mariupol when shells rained down a month ago.

While a fragile two-week-old ceasefire shows signs of holding, Kiev yesterday said pro-Russian separatists are using the truce to regroup their forces, especially around Mariupol, a strategically important port city in Ukraine’s southeast.

Control of the industrial hub would help the rebels form a corridor to the Crimea peninsula which Russia annexed from Ukraine last year.

Since the truce, they have said they aim to win the city through negotiation, not force of arms. Aware there is no provision for that in the latest internationally brokered peace accords, Mariupol’s residents are holding their breath.

When we capture fighters from the other side, they have top-of-the-range modern guns

The shelling on January 24 killed thirty people in the district of Vostochnaya where she runs her stall. Government troops and rebels have been vying for control of the nearby village of Shyrokyne, each accusing the other of provoking the other side to attack.

The guns have fallen silent in recent days, but on Friday Ukraine’s military said it had tracked a convoy of GRAD missile systems and other military equipment leaving the separatist stronghold of Donetsk in the direction of Mariupol.

Kiev also says military equipment from Russia has been spotted crossing the border by Novoazovsk, east of Mariupol, since the start of the ceasefire, aimed at ending a conflict in which over 5,600 have been killed. The separatists, who seized Mariupol briefly as they swept through eastern Ukraine last year, say it should be theirs.“If Putin decides he wants Mariupol then they will take it, they’re better armed than us,” said national guard soldier Vitaly Mashtabei, stationed near Vostochnaya.

“When we capture fighters from the other side, they have top-of-the-range modern guns and most of our guys only have the old Soviet stuff,” he said. Kiev and its Western allies say the rebels are funded and armed by Moscow, and backed by Russian military units. Moscow is still denying that it is aiding sympathisers in Ukraine.

Rebels initially disavowed the ceasefire deal to seize the transport hub of Debaltseve, which they had also claimed as their own, in a humiliating defeat for government troops that destroyed most of the town’s strategic infrastructure.

Asked about a possible offensive on Mariupol, Denis Pushilin, who represented the rebels at the talks which brokered the peace deal, said last week they would choose negotiation.

“We’ll do everything possible to make it happen through political means,” Russian media quoted Pushilin as saying.

Prime Minister Arseny Yatseniuk accused separatists of trying to destabilise Mariupol, where Russian and Ukrainian sympathisers live side by side, by disrupting supplies to its steel plants from the Avdiivka coke plant, around 100 km to the north.

“They are intentionally bombing Avdiivka to destroy the coke plant, so that Mariupol’s factories close, so there’s a social revolt in Mariupol,” he said in a televised interview on Friday.

The Ukrainian military said yesterday GRAD rockets had been fired at Avdiivka and tanks had fired at government troops stationed there.

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