The British Defence Secretary Ben Wallace has warned on Wednesday that Vladimir Putin has “no limit” to the brutal force he will use and will use indiscriminate carpet bombings against Ukrainian cities.

Wallace said Putin is “ruthless” and he is prepared to use his military to siege Ukraine’s population centres and the second largest city, Kharkiv has had many days of a heavy bombardment.

The Ministry of Defence said the latest intelligence says there has been “heavy Russian artillery and air strikes have targeted built-up areas in Kyiv, Kharkiv, Mariupol and Chernihiv.”

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Wallace said the advance of Russian forces continues to be slowed by a combination of overstretched logistics, poor morale, crying Russian troops and brave resistance by Ukrainian fighters.

“The Russians are considerably behind their schedule, by days not hours, and that leads to stresses on their logistical supply chains,” he told the BBC.

“That’s why you have seen some of these columns fairly grind to a halt.

“They have also been surprised by the strength of the Ukrainian resistance.”

He told BBC Breakfast that “none of the major cities have been taken control of.”

There was “huge amounts of low morale in the Russian forces, we’ve seen lots of surrenders.

“But that doesn’t take away from the fact you have a very ruthless Russian armed forces leadership and a president who seems to know no limit to how much violence they will use to achieve their aims.”

He told the BBC that siege tactics were in the Russian military doctrine, with thousands of forces surrounding a city before they “bombard it indiscriminately and then eventually close in on a population that they hope to have broken, and indeed take over what’s left of the city.

“We’ve seen that in Chechnya before,” he said.

Wallace told Sky News that meant a plan to “carpet-bomb cities, indiscriminately in some cases.”

The British Defence Secretary told BBC Radio 4’s Today and warned Russian troops will “pummel these cities with artillery and then hope to break the city.”