Donetsk and Luhansk have demanded that Kyiv lift the transport blockade of Donbas before spring.
"By using radicals, Kyiv has organized and is maintaining the railroad blockade and is threatening to block motorways connecting the Donbas republics to Ukraine," Alexander Zakharchenko and Igor Plotnitsky, heads of the "DPR" and "LPR", said in a joint statement posted on the Luhansk information center's website.
"We have to declare that, unless the blockade is lifted by 00:00 a.m. on Wednesday (March 1, 2017), we will appoint external management at every enterprise under Ukrainian jurisdiction operating in the DPR and the LPR," the statement said.
The DPR and LPR would also stop coal supply to Kyiv, the statement says.
"We will stop coal supply to Ukraine. There is neither the possibility nor a payment plan for coal supplies," it said.
Zakharchenko and Plotnitsky also believe the transport blockade of Donbas is at variance with the Minsk Agreements.
"It goes directly against both the spirit and the letter of the Minsk Agreements and generally characterizes this Ukrainian leadership as one unable to take care of its citizens. Many enterprises have been forced to cease operation as a result of the Kyiv authorities' criminal actions," the statement says.