The United States brandished the threat of economic sanctions on Russia on Sunday, with Secretary of State John Kerry calling Moscow's moves on Ukraine an "incredible act of aggression."

As Washington's already strained relations with Moscow deteriorated further, Kerry was scathing in his condemnation and said the United States has "all options on the table" including a military response.

But, doing the rounds of Sunday morning television news shows to stress the Obama administration's disapproval of Russia's actions, Kerry emphasized a U.S. desire for a peaceful resolution to the crisis.

Ignoring warnings from President Barack Obama and other Western leaders, President Vladimir Putin won permission from his parliament on Saturday to use military force. The stated purpose was to protect Russian citizens in Ukraine following the ouster of the country's Russian-backed president a week ago.

Russian forces have already bloodlessly seized Crimea - an isolated Black Sea peninsula with a majority of Russian speakers and where Moscow has a naval base.

"You just don't in the 21st century behave in 19th century fashion by invading another country on completely trumped up pretext," Kerry told the CBS program "Face the Nation."

Kerry spoke of "very serious repercussions" for Moscow and said G8 nations and some other countries are "prepared to go to the hilt to isolate Russia" with an array of options available.

"They're prepared to put sanctions in place, they're prepared to isolate Russia economically, the ruble is already going down. Russia has major economic challenges," he said.

Kerry listed visa bans, asset freezes, trade isolation, and investment changes as possible steps, adding: "American businesses may well want to start thinking twice about whether they want to do business with a country that behaves like this."

Obama appeared before television cameras on Friday evening to warn Putin that there would be "costs" for any military intervention in Ukraine.

He also spent 90 minutes on the telephone with the Russian leader on Saturday. Kerry said Obama told Putin "that it was imperative to find a different path, to roll back this invasion and un-do this act of invasion."

Obama faced criticism at home from Republican lawmakers who called his response so far weak.

"Every time the president goes on national television and threatens Putin or anyone like Putin, everybody's eyes roll, including mine. We have a weak and indecisive president that invites aggression," Senator Lindsey Graham, a leading Republican voice on foreign policy and a frequent Obama critic, told the CNN program "State of the Union."

Mike Rogers, the chairman of the U.S. House of Representatives Intelligence Committee, said on "Fox News Sunday" that "I think Putin is playing chess and I think we're playing marbles,"

"And I don't think it's even close," Rogers added.

Ukraine mobilized for war on Sunday after Putin asserted the right to invade Russia's neighbor. The crisis is the most significant showdown with the West since the end of the Cold War a quarter century ago.

"It's an incredible act of aggression. It is really a stunning, willful choice by President Putin to invade another country. Russia is in violation of the sovereignty of Ukraine. Russia is in violation of its international obligations," Kerry said.

The United States and several allies including Britain and France have already started deploying one weapon of isolation, announcing they are suspending taking part in preparations for a G8 meeting in Sochi, Russia, in June. The city also hosted the Winter Olympic Games last month.

Kerry said the United States is "absolutely prepared" to boycott the Sochi summit. He said recent events "put at question Russia's capacity to be within the G8," the group of major industrialized nations that Russia joined in 1998.

"If Russia wants to be a G8 country, it needs to behave like a G8 country," Kerry added.

Obama canceled a visit to Moscow last September to protest Putin's refusal to help rein in Syrian President Bashar Assad in that country's civil war, although he did attend a G20 summit in St. Petersburg.

Republican Graham called for suspending Russian membership in the G8 and the wider G20 for at least a year, "and for every day they stay in Crimea, add to the suspension. Do something."

Kerry also called on the U.S. Congress to work with the Obama administration on an economic package to assist Ukraine.

The crisis began in November after Viktor Yanukovich, Ukraine's then president, triggered protests by spurning a political and trade deal with the European Union.