WASHINGTON: The Obama administration announced $1 billion in economic and energy aid to Ukraine on Tuesday as Congress moved to bring economic sanctions against Russia for sending troops to the Crimean region.

Already outmanoeuvred by Russia, the Obama administration is now focusing its attention on shoring up the pro-Western government in Kiev.

US Secretary of State John Kerry arrived in Kiev early on Tuesday to reaffirm Washington’s “strong support for Ukrainian sovereignty, independence, territorial integrity, and the right of the Ukrainian people to determine their own future, without outside interference or provocation,” the State Department said.

On Monday, the US Defence Department “put on hold” all military-to-military engagements with Russia.

But US lawmakers and senior government officials acknowledge that they cannot counter Russia’s military move in Ukraine.

“There is not a military option that can be exercised now,” said Republican Senator John McCain as three senior Obama officials agreed.

“Frankly, our goal is to uphold the territorial integrity and sovereignty of Ukraine, not to have a military escalation,” said one of them while briefing the media. “We are focused on political and economic and diplomatic options.”

US Treasury Secretary Jack Lew announced a $1bn economic package to “help the Ukrainian government implement the reforms needed to restore financial stability and return to economic growth”.

At the US Senate, lawmakers also introduced a bipartisan legislative package to help Ukraine, which is teetering on the brink of economic collapse.

The legislation will authorise funds to provide at least $1bn in loan guarantees to provide structural support to Ukraine’s economy.

“The steps Russia has taken are a violation of Ukraine’s sovereignty, Ukraine’s territorial integrity,” US President Barack Obama said on Monday. “They’re a violation of international law.”

In televised remarks on Tuesday, Russian President Vladimir Putin said he reserved the right to protect Russian-speaking people in Ukraine in the wake of what he called “an anti-constitutional” coup that toppled a pro-Russia president.

Mr Putin, who said that full military force is a “last resort”, added that he would not be deterred by economic sanctions from the West. “All threats against Russia are counter-productive and harmful,” he said.

At the Pentagon, Press Secretary Navy Rear Adm John Kirby said the suspended joint activities with Russia included exercises, bilateral meetings, port visits and planning conferences. “We call on Russia to de-escalate the crisis in Ukraine and for Russian forces in Crimea to return to their bases, as required under the agreements governing the Russia Black Sea Fleet.”