With a historic sweep of his pen, President Vladimir Putin signed a treaty Tuesday to annex Crimea, eliciting strong condemnations from Western leaders and NATO officials. 

In an emotional 40-minute speech that was televised live from the Kremlin, Putin said "in people's hearts and minds, Crimea has always been an integral part of Russia."

He dismissed Western criticism of Sunday's Crimean referendum in which residents of the strategic Black Sea peninsula overwhelmingly backed breaking off from Ukraine and joining Russia as a manifestation of the West's double standards.

At the same time, the Russian leader said his nation didn't want to move into other regions of Ukraine, saying "we don't want division of Ukraine."

Putin argued that months of protests in Ukrainian capital that prompted President Viktor Yanukovych to flee to Russia had been instigated by the West in order to weaken Russia. He cast the new Ukrainian government as illegitimate, driven by radical "nationalists, neo-Nazis, Russophobes and anti-Semites."

Following the speech before lawmakers and top officials, Putin and Crimean officials signed a treaty for the region to join Russia.

The treaty will have to be endorsed by Russia's Constitutional Court and ratified by both houses of parliament, but Valentina Matviyenko, the speaker of upper house of Russian parliament, said the procedure could be completed by the end of the week.

In his speech at the Kremlin's white-and-gold St. George hall, Putin said the rights of ethnic Russians in Ukraine had been abused by the new Ukrainian government. He insisted that Crimea's vote Sunday to join Russia was in line with international law and reflected its right for self-determination.

UKRAINE-CRISIS/

Crimea formally applied to join Russia on Monday after its leaders declared a Soviet-style 97-per cent result in favour of seceding from Ukraine in a referendum condemned as illegal by Kyiv and the West that triggered immediate sanctions. (Sergei Karpukhin/Reuters)

Putin's speech came just hours after he approved a draft bill for the annexation of Crimea, a key move in a flurry of steps to formally take over the Black Sea peninsula.

To back his claim that Crimea's vote was in line with international law, Putin pointed to Kosovo's independence bid from Serbia — supported by the West and opposed by Russia — and said that Crimea's secession from Ukraine repeats Ukraine's own secession from the Soviet Union in 1991.

He denied Western accusations that Russia invaded Crimea prior to the referendum, saying Russian troops were sent there in line with a treaty with Ukraine that allows Russia to have up to 25,000 troops at its Black Sea Fleet base in Crimea.

Putin had previously warned that he would be ready to use "all means" to protect Russian speakers in eastern Ukraine, and Russia has built up its forces alongside the border between the two countries, raising fears of an invasion.

Western allies fire back 

The U.S. immediately fired back, with Vice President Joe Biden condemning Putin's actions and vowing to impose more sanctions against Russia.

POLAND/ Joe Biden arrives

U.S. Vice President Joe Biden arrives in Warsaw on Tuesday. During his trip to the region, Biden is set to speak about the Ukraine crisis with the leaders of Poland, Estonia and Lithuania. (Kacper Pempel/Reuters)

Biden, speaking in Warsaw next to Polish Prime Minister Donald Tusk, said the world has seen through Russia's actions in Crimea, which he called "nothing more than a land grab."

Biden says virtually the entire world rejects the referendum in Crimea that cleared the way for Russia to annex the peninsula in Ukraine.

Tusk said the Crimea crisis was "Not just a problem for Ukraine ... the Russian action in Ukraine is a challenge for the whole free world."

G7 leaders to talk Ukraine at The Hague

The United States and its G7 allies will gather next week at The Hague to consider further response to Russia's attempt to absorb Ukraine's Crimea region, the White House said on Tuesday.

The meeting will take place on the margins of a nuclear security summit at The Hague that U.S. President Barack Obama plans to attend.

"The meeting will focus on the situation in Ukraine and further steps that the G7 may take to respond to developments and to support Ukraine," said White House National Security Council spokeswoman Caitlin Hayden.

On Monday, the White House imposed asset freezes on seven Russian officials, including Putin's close ally Valentina Matvienko, who is speaker of the upper house of parliament, and Vladislav Surkov, one of Putin's top ideological aides. The Treasury Department also targeted Yanukovych, Crimean leader Sergei Aksyonov and two other top figures.

Speaking in Washington, D.C., on Tuesday afternoon, White House spokesperson Jay Carney strongly hinted that subsequent rounds of sanctions in response to the Crimea move could include some of the powerful and wealthy oligarchs who have close ties to Putin.

"I think anyone who understands how the Russian system of governance works and who has influence in that system understands the kind of person that we're talking about here, and the fact that they have substantial assets, not just in Russia, but abroad," he said.

Canadian Foreign Affairs Minister John Baird condemned Putin's speech to reporters on Tuesday afternoon, and revealed that the Canadian government would be imposing new sanctions on an additional 17 Russian and Ukrainian individuals. 

British Prime Minister David Cameron, reflecting Western worries that Putin's encroachment could spread farther in Ukraine and beyond, said the Russian moves were "in flagrant breach of international law and send a chilling message across the continent of Europe."

"President Putin should be in no doubt that Russia will face more serious consequences," Cameron declared.

Holding out hope for a diplomatic way out of the crisis, Cameron added, "The choice remains for President Putin: Take the path of deescalation or face increasing isolation and tighter sanctions."

NATO Secretary General Anders Fogn Rasmussen also released a statement Tuesday, stating "there can be no justification to continue on this course of action that can only deepen Russia's international isolation. Crimea's annexation is illegal and illegitimate and NATO Allies will not recognize it."

New concerns in Ukraine as Russia ignores sanctions

Ukraine's Prime Minister Arseniy Yatsenyuk said in a televised statement that Ukrainian law-enforcement agencies have gathered "convincing evidence of the participation of Russian special services in organizing unrest in the east of our country."

UKRAINE-CRISIS/MOBILISATION

Members of a 'Maidan' self-defense battalion take part in a training at a Ukrainian Interior Ministry base near Kyiv. Ukraine's parliament, seeking to boost the country's military force in the face of Russia's takeover of the Crimea peninsula, endorsed a presidential decree on Monday to carry out a partial mobilization involving 40,000 reservists. (Gleb Garanich/Reuters)

Many in the ethnic Tatar minority in Crimea were wary of the referendum, fearing that Crimea's break-off from Ukraine would set off violence against them.

Crimean Deputy Prime Minister Rustam Temirgaliyev seemed to confirm those fears, saying in remarks carried by the RIA Novosti news agency that the government would ask Tatars to "vacate" some of the lands they "illegally" occupy so authorities can use them for "social needs."

The Russian State Duma, the lower chamber of parliament, on Tuesday unanimously passed a resolution condemning U.S. sanctions targeting Russian officials including members of the chamber. The chamber challenged President Barack Obama to extend the sanctions to all the 353 deputies who voted for Tuesday's resolution, suggesting that being targeted was a badge of honour. Eighty-eight deputies left the house before the vote.

Putin's senior foreign policy adviser Yuri Ushakov blasted the new sanctions in an interview with Russian news agencies. “We are fed up with these sanctions,” Ushakov said.

“They provoke only feelings of irony and sarcasm.”

With files from Reuters