A slide in Russian revenue from oil and gas clashed against the Kremlin ramping up spending on its nearly year-long war against Ukraine, resulting in a wider budget deficit for the country in January. Oil and gas revenue tumbled 46% in January from the same month a year ago to 426 billion rubles ($5.96 billion), Russia's finance ministry said Monday in a preliminary release. It attributed the decline largely to a drop in prices for its Urals blend — its largest crude oil export — and to a fall in exports for natural gas. Russia sold Urals at an average...