Fears over the stability of a ceasefire in eastern Ukraine continued to escalate as pro-Kiev forces reported 120 separate attacks in 24 hours. The ceasefire is due to come into effect on Saturday night.

Ukraine’s military said on Saturday that pro-Russian forces had tried overnight to storm government positions on the edge of the strategic battleground town of Debaltseve, where Kiev denies rebels have trapped thousands of its troops.



“There has been no lull. Moreover, rebels continue attacks on Debaltseve,” military spokesman Anatoly Stelmakh said.

The key transport hub, northeast of Donetsk, has been the focus of some of the fiercest fighting in recent weeks.



Pro-Russian forces also were trying to seize control of Mariupol before the truce began at 2200 GMT, the Ukrainian defence ministry said.



The city is on the Azov Sea and there are fears that the rebels aimed to seize it as a step towards establishing a corridor between mainland Russia and the Crimean peninsula that Russia annexed 11 months ago.

Officials said a series of artillery attacks hit areas near Mariupol on Saturday morning, but there was no immediate information on casualties.



The ceasefire negotiated by European leaders this week also envisages a withdrawal of the heavy weapons responsible for many of the almost 5,500 casualties in the conflict that broke out almost a year ago.



The new Minsk agreement is broadly similar to an earlier failed deal in September, except that the new heavy weapons-free zone will be 31 to 87 miles wide, depending on the range of the weapon. That is double the width of the buffer zone agreed in September.

However, there are fears about whether forces on either side of the conflict will comply with the truce.



The ceasefire and weapons pullback will be monitored by the Organisation for Security and Co-operation in Europe and the UN Security Council is expected to meet on Sunday for an emergency session to shore up the ceasefire deal.

The US said it believed Russia was continuing to deploy heavy weapons ahead of the ceasefire.

Jen Psaki, state department spokeswoman, said the Russian military had deployed large amounts of artillery and rocket launcher systems and was using them to shell Ukrainian positions.

Meanwhile, the Ministry of Defence confirmed that Ukraine had taken delivery of former British military armoured vehicles in a commercial arms deal.

Reports in Ukraine said 20 Saxon armoured personnel carriers had been delivered and a further 55 were to follow but the MoD did not confirm the figures.

An MoD spokeswoman said the unarmed vehicles were transferred by a private company under a 2013 deal that pre-dated the current conflict.

The Saxon vehicles – described as troop transporters not considered suitable for close combat – were first used by the MoD in the 1980s but went out of service three years ago, the spokesman said.