"You have to look over the period of time Russia went into Crimea, since we've imposed sanctions, there has been a quite substantial deterioration in Russia's already weak economy," Lew told a House Appropriations subcommittee hearing Tuesday. "We see it in their stock exchange, we see it in their exchange rate, we see it in a number of important economic indicators."
Lew faced skeptical members of Congress from both sides of the aisle a day after White House announced additional sanctions, targeting seven individuals and 17 companies, including travel restrictions and the freezing of assets, and said further action could still come.
"We need to continue to keep our options open," Lew said. "We are prepared to take more action and we've made clear that we're prepared to take more action if the policy of Russia doesn't change."
The new U.S. sanctions include Dmitri Kozak, the deputy prime minister; Vyacheslav Volodin, deputy chief of staff to President Vladimir Putin; Alexei Pushkov, the chairman of the international affairs committee of the Duma, and Igor Sechin, president of the state-owned Rosneft oil company.
The European Union issued sanctions of its own Tuesday, targeting 15 Russian individuals that also included Kozak as well as first deputy Defense Minister Valery Gerasimov, and pro-Russian separatists in Ukraine, including the self-declared leader of the "Donetsk People's Republic," Denis Pushilin.
Notable deaths of 2014 [PHOTOS]