KIEV, March 15 – Naftogaz Ukrayiny will increase claims against Russia's Gazprom under the gas transit contract by $1 billion at the end of the first quarter, Business Development Director Yuriy Vitrenko said.

"We will accrue around $1 billion for Gazprom for the first quarter of 2016 as insufficient payment under the [gas] transit contract," he wrote on his Facebook page.