Putin has promised to protect a bank that is partially owned by an old ally, which the US has blacklisted. Russia's response will be in kind to the latest financial and visa restrictions, after imposing its own blacklist. Despite allies laughing off the US sanctions, shares on the Moscow stock exchange have taken a sharp fall. President Obama has threatened to target major sectors of the economy if Russia advances into areas of Ukraine beyond the Black Sea peninsula. Washington and the OSCE are skeptical of Russian assurances about troop movements on the Ukraine border, and the financial pressure is increasing with Visa and MasterCard halting processing payments for a Russian bank owned by individuals on the US blacklist. The EU has also imposed sanctions on Russian officials and expressed a desire to reduce reliance on Russian energy. Putin has signed a law ratifying Crimea's annexation into Russia and creating two new Russian administrative districts. Celebration in Crimea was marked by fireworks, while some Ukrainian and Tatar residents remained cautious. The recent referendum in Crimea, which resulted in overwhelming support for union with Russia following the seizure of the region by Russian troops, was criticized by the US and EU as illegitimate. This paved the way for Crimea's annexation by Russia. President Obama's decision to target the financial interests of those close to Putin, from his time as mayor of St Petersburg to his presidency, has escalated tensions. Putin denied that Bank Rossiya, a St Petersburg-based bank owned by Putin's associate Yuri Kovalchuk, played a role in the events in Crimea. Putin, who believes Crimea acted in self-determination, pledged to move his wages to Bank Rossiya. Other individuals on the US blacklist include prominent figures in the Russian energy sector. European leaders also discussed improving energy security in light of Russia's significant role as a supplier of oil and gas to the EU, with plans to negotiate joint supply deals with Moscow to enhance bargaining power. "It is evident that we must progress towards an energy union," declared Van Rompuy. Merkel suggested that US shale gas could potentially be an alternative for European countries looking to diversify. Obama is set to discuss this at a summit with EU leaders next Wednesday. The US applied pressure through the international financial system by having Visa and MasterCard cease services for transactions with Russia's SMP bank, causing concern among foreign banks and companies about potential ripple effects from the sanctions. A French banker in Moscow stated that the current sanctions were merely superficial and the main risk lay in US dollar transfers, crucial for Russia's energy export-focused economy. Obama mentioned the possibility of further sanctions on sectors like financial services, oil and gas, metals and mining, and the defense industry if Russia escalated military action in eastern and southern Ukraine. Meanwhile, Ukrainian troops in Crimea, surrounded by Russian forces, continued to evacuate their bases, unable to resist Moscow's control of the peninsula. German Foreign Minister Frank-Walter Steinmeier expressed concern over the continuing instability in Ukraine and urged OSCE observers to resume their work promptly. European governments, including Germany and France, took measures against Russia, such as suspending defence-related exports and halting military cooperation. The EU leaders in Brussels showed support for Ukraine's new leadership by signing a political agreement with interim Prime Minister Arseniy Yatseniuk and promising financial aid once a deal is reached with the IMF. The IMF is expected to announce details of a loan program linked to economic reforms next Tuesday. The protests in Ukraine were sparked by former President Yanukovich's refusal to sign an association agreement with the EU. Russia's stock index declined initially due to concerns over sanctions imposed by the US, with credit ratings agencies warning of a negative outlook for Russia's economy. Prime Minister Dmitry Medvedev stated that Russia would increase financial pressure on Ukraine, demanding repayment of $11 billion under a gas supply contract.