By Li Hongmei

Russian President Vladimir Putin answered President Obama's announced sanctions against a handful of officials in Putin's inner circle - but not Putin, himself - by signing a treaty Tuesday making Crimea a part of Russia.

The signing follows a referendum on Sunday in which residents of Ukraine's southern region overwhelmingly backed the move. The treaty still must be approved by Russia's Constitutional Court and ratified by both houses of parliament. Those steps are considered mere formalities.

Putin signed the treaty with Crimea's prime minister and parliament speaker following a televised address to the nation, in which he vigorously defended Crimea's vote as a restoration of historical justice.

Putin has accused the West of encouraging unrest in Ukraine in order to break its historic ties with Russia, and dismissed Western criticism of the Crimean vote as illegitimate.

A Ukrainian military spokesman said that one Ukrainian serviceman was killed and another injured when a military facility in Crimea was stormed Tuesday by armed men just hours after Putin's speech.

The officer was shot in the chest, the Ukrainian Defense Ministry told Fox News, adding that the Ukrainian government now is allowing its soldiers to use firearms to defend themselves.

The armed men were dressed in uniforms similar to Russian military uniforms and appeared in trucks previously stolen from the Ukrainian military base, the Ministry said.

The attackers took over the base, confiscated documents, arrested the Ukrainian soldiers and are now controlling the base.

The sanctions ordered by Obama include freezing any assets in the U.S. and banning travel into the country of seven ranking Russian government officials and four Crimea-based separatist leaders, Reuters reported.

According to the Washington Post, the Russians targeted include top Putin aides Sergei Glazyev and Vladislav Surkov, Deputy Prime Minister Dmitry Rogozin, and parliament leaders.

Some of the Russians mocked the sanctions, the Post reported.

"I quite like the company I have found myself in," Andrei Klishas, chairman of the Russian Federation Council's Constitutional Legislation Committee, told the Interfax news service.

"I don't have any accounts or real estate in the U.S., and as regard private visits, I'll have to do without them," Leonid Slutsky, who heads a parliamentary committee on Eurasian integration, said, according to the Post.

In a televised address to Russia Tuesday, Putin defended Russia's move to annex Crimea, saying that the rights of ethnic Russians have been abused by the Ukrainian government.

He also called authorities in Ukraine "nationalists, neo-Nazis, Russophobes and anti-Semites," according to Reuters.

"Those who were behind recent events, they were ... preparing a coup d'etat, another one," Putin said. "They were planning to seize power, stopping at nothing."

He denied Western accusations that Russia invaded Crimea prior to a referendum vote there, 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 also said that Crimea's vote Sunday to join Russia is in line with international law, reflecting its right for self-determination.

He pointed at the example of Kosovo's independence bid, supported by the West, and said that Crimea's secession from Ukraine repeats Ukraine's own secession from the Soviet Union in 1991.

"Our Western partners headed by the United States prefer not to be guided by international law in their practical policies, but by the rule of the gun,'' he told a joint session of parliament, according to Reuters. "They have come to believe in their exceptionalism and their sense of being the chosen ones. That they can decide the destinies of the world, that it is only them who can be right."

Putin added that he will never seek to spark a confrontation with the West, but said he would defend Russia's interests.