Live Blog: Crisis In Ukraine (Archive)

"I believe [Ukraine's President-elect Petro Poroshenko's] inauguration provides an opportunity particularly since he has demonstrated a commitment to reach out to the east and pursue reforms. Russia needs to seize that opportunity. Russia needs to recognize that President-elect Poroshenko is the legitimately elected leader of Ukraine and engage the government in Kyiv." -- Obama

"Given its influence over the militants in Ukraine, Russia continues to have a responsibility to convince them to end their violence, lay down their weapons and enter into a dialogue with the Ukrainian government." -- Obama

"The status quo is unacceptable. The continuing destabilization of eastern Ukraine must stop. Second, there are a set of things that need to happen. [Russian] President [Vladimir] Putin must recognize the legitimate election of President Poroshenko, he must stop arms crossing the border into Ukraine, he must cease Russian support for separatist groups. And third if these things don't happen then sectoral sanctions will follow." -- Cameron

"Today we are creating a new country. A country for its citizens, a country of free and dignified people. The changes in our country will stem from the capital, they will stem from Kyiv."

"I declare that as of today there will be zero tolerance for corruption in Kyiv."

"I, Vitali Klitschko, assuming the position of Kyiv city mayor, swear -- realizing my great responsibility -- that I will faithfully serve the community of Kyiv and the people of Ukraine."

Vitali Klitschko has been sworn in as mayor of Ukraine's capital Kiyv.

In a speech to the city assembly on June 5, the former boxing champion promised "zero tolerance for corruption."

Klitschko, who heads the UDAR party, emerged as one of the leaders of pro-European protest movement that ousted President Viktor Yanukovych from power in February.

He won nearly 57 percent in the election for Kiyv mayor, which was held at the same time as Ukraine's presidential election on May 25.

Klitschko had earlier withdrawn a bid to run for president and backed billionaire Petro Poroshenko instead.

Poroshenko, who won the presidential election, will be sworn in on June 7.

U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov have said that Ukraine should be a peaceful, stable, and prosperous bridge between Russia and Europe.

Speaking before meeting Lavrov in Paris on June 5, Kerry said the Ukrainian people should be "able to act as a bridge between East and West.”

He expressed hope that Washington and Moscow will "find a way to cooperate on how to make this happen."

Lavrov agreed, adding that Moscow would like to see all those who live in Ukraine "to be feeling equal, respected, and listened to, living in peace being a bridge, not being a pawn."

He said Russia would "like to see other countries like Iraq, Libya, Syria, many others also to be in peace, not to be used as a pawn."

"[Ukraine's President-elect Petro Poroshenko] intends to make a major effort to bring the country together. This is an opportunity, we hope, for Russia, the United States and others, all of them to come together in an effort to try to make a Ukraine that is strong economically, whose sovereignty is respected, whose independence is respected, but which clearly is not the pawn in a tug of war between other nations, but rather an independent, sovereign country, with the integrity of its borders and people, able to act as a bridge between East and West." -- Kerry

"We would like to see Ukraine a peaceful, stable place for all those who live in Ukraine, for them to be feeling equal, respected, and listened to, living in peace being a bridge not being a pawn." -- Lavrov

Ukraine says it has closed two border crossings with Russia after heavy fighting with pro-Russian insurgents.

The Border Guard Service said on June 5 that the posts in the eastern Luhansk region were "closed" and border guards had withdrawn because of the "extreme escalation" in the security situation.

The agency also said that fighting was continuing at the Marinovka post in the Donetsk region after separatists attacked the border post overnight.

Border guards have frequently clashed with the separatists who on June 2 attacked their headquarters in Luhansk.

Ukraine's government says fighters are crossing over from Russia.

Russia says thousands of refugees have crossed the border in the other direction, a claim Ukraine denies.

Russian Foreign Ministry spokesman Aleksandr Lukashevich said on June 5 Ukraine's plans to close the border were "outrageous and inadmissible."