The United States on Monday imposed sanctions on seven Russian officials and 17 firms linked to President Vladimir Putin's inner circle to punish what it said were "provocative acts" in Ukraine.
Washington is also tightening licensing requirements for certain hi-tech exports to Russia that could have a military use, the White House announced in a statement issued in Manila, where President Barack Obama is on a state visit.
"The United States has taken further action today in response to Russia's continued illegal intervention in Ukraine and provocative acts that undermine Ukraine's democracy and threaten its peace, security, stability, sovereignty, and territorial integrity," said White House spokesman Jay Carney in a statement.
Carney said Russia had done nothing to meet the terms of a deal agreed in Geneva with Ukraine, the European Union and the United States and designed to rein in pro-Moscow separatists in eastern Ukraine.
"Russia's involvement in the recent violence in eastern Ukraine is indisputable," he said.
The sanctions follow up on previously announced measures targeting other members of Putin's political and inner circle and a Russian bank.
They do not however specifically target sectors of the Russian economy like energy and mining.
The White House said those measures would only be imposed by the United States and its European allies if Russia actually invades Ukraine.
The companies sanctioned include Avia Group limited, the Severny Morsoy Bank, InvestCapital Bank, Transoil, Volga Resources Group, SMP Bank, Sobin Bank and Zest Leasing.
Individuals hit with visa bans and asset freezes include Oleg Belavantsev, who was named presidential envoy to Crimea by Putin in March.
Sergei Chemezov, director general of Rostec, the state development manufacturing and export programme for hi-tech exports, is also on the list. The US Treasury said Chemezov is a trusted aide to Putin.
Deputy prime minister Dmitry Kozak is hit by sanctions, along with Evgeniy Murov, director of Russia's Federal Protective Service.
State Duma Deputy Aleksei Pushkov is among those named along with Igor Sechin, president and chairman of the Management Board for Rosneft, Russia's top petroleum company and one of the world's largest publicly-traded oil companies.
"Sechin has shown utter loyalty to Vladimir Putin -- a key component to his current standing," the Treasury said.