The US has denied any role in the death of an Iranian nuclear scientist in a bomb blast in Tehran yesterday. Washington has won the backing of Japan for tougher sanctions against Iran over its nuclear program. Russia still opposes said sanctions, Reuters reports, and has urged both sides to refrain from inflaming the situation. As the possibility of a new gas spat looms, Ukraine has threatened to reduce purchases of Russian gas by 50%. Whether it cuts imports or not, Kiev must pay for unused gas ordered under its 2009 contract with Russia, maintains Gazprom head Alexei Miller. President Medvedev has commissioned Igor Artemyev, Director of the Federal Antimonopoly Service to ensure that petrol prices remain reasonable. Minority shareholders in TNK-BP have apparently sought assistance from the Russian president in protecting their rights as they seek damages from the board representatives of the TNK’s British partner. A former president of SOCAR, Azerbaijan’s state oil company, tells the Moscow Times that competition between Azerbaijan and Russia for natural gas sales markets in Europe will rise, to the EU’s benefit. Thanks to increased shale fracking, natural gas production in the US is apparently expected to increase to record levels this year and in 2013. Find out here why Royal Dutch Shell’s chief believes that the potential for shale gas exploration in Europe is limited.