As the European Union (EU) approved tougher sanctions against Russia on Tuesday, U.S. President Barack Obama also swiftly announced new penalties.

The EU has agreed on a package of "significant" additional restrictive measures targeting Russia's finance, defense and energy sectors, said the European Council in a statement.

These decisions will limit access of Russian state-owned financial institutions to EU capital markets, impose an arms embargo, establish an export ban on dual-use goods for military end users, and curtail Russian access to sensitive technologies particularly in the field of the oil sector, according to the statement.

The broad EU economic sanctions are intended to be "a strong warning" and "a powerful signal" to Russia that "destabilizing Ukraine or any other Eastern European neighboring country will bring heavy costs to its economy," said the statement.

Meanwhile, the EU also emphasized that it remains ready to reverse its decisions, and re-engage with Russia "when it starts contributing actively and without ambiguities to finding a solution to the Ukrainian crisis."

Following its European allies, Obama announced an expansion of U.S. penalties targeting key sectors of Russia's economy.

Building on measures unveiled two weeks ago, the United States expanded its sanctions to more Russian banks and defense companies, and blocked the export of specific goods and technology to Russia's energy sector, Obama told reporters at the White House.

He said that the United States is formally suspending credit that encourages exports to Russia or finances economic development projects in Russia.

"If Russia continues on this current path, the costs on Russia will continue to grow," said the president.

The U.S. Treasury Department said in a statement that the United States imposed sanctions against three state-owned Russian banks. It also designated and blocked the assets of United Shipbuilding Corp., a defense technologies firm based in St. Petersburg.

"The major sanctions we're announcing today will continue to ratchet up the pressure on Russia, including the cronies and companies that are supporting Russia's illegal actions in Ukraine," Obama said, adding that the existing sanctions had made a weak Russian economy even weaker.

After the EU and the United States rolled out new measures targeting Russia, Canadian Prime Minister Stephen Harper also announced more sanctions against Russia for Moscow's support for rebels in Ukraine.

"Canada is announcing its intent to once again increase economic and political pressure, in the coming days, by imposing additional sanctions on the regime and those closest to it," Harper said in a statement on Tuesday.

These punitive measures from the EU, the United States and other Western countries are driven by allegations that Russia has been involved in the July 17 downing of the Malaysia Airlines flight MH17, which killed all 298 people on board.

Russia, which has been calling for a thorough and objective investigation by international experts on the plane crash, will not impose tit-for-tat measures or act "hysterically" over Western economic sanctions, Russian Foreign Minister Sergei Lavrov said earlier.