MOSCOW — With a historic sweep of his pen, President Vladimir Putin signed a treaty today to annex Crimea, describing the move as correcting past injustice and a necessary response to what he called Western encroachment upon Russia’s interests.

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.”

Thousands of Russian troops have been massed along Ukraine’s eastern border for the last few weeks — Russia says that was for military training while the U.S. and Europe view the troops as an intimidation tactic.

Putin argued that months of protests in Ukrainian capital that prompted President Viktor Yanukovych to flee to Russia had been instigated by the West 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 Crimea’s vote Sunday to join Russia was in line with international law and reflected its right for self-determination.

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 Crimea’s secession from Ukraine repeats Ukraine’s own secession from the Soviet Union in 1991.

He denied Western accusations Russia invaded Crimea before 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 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.