EU leaders have signed an agreement on closer relations with Ukraine, in a show of support following Russia's annexation of Crimea, BBC News reports.

Ukraine's interim PM Arseniy Yatsenyuk and the EU signed the deal in Brussels.

Pro-Moscow President Viktor Yanukovych's abandonment of the deal had led to deadly protests, his removal and Russia taking over Crimea.

On Friday, March 21, Russia's upper house unanimously approved the treaty on Crimea joining the Russian Federation.

The EU Association Agreement is designed to give Ukraine's interim leadership economic and political support.

EU President Herman Van Rompuy said in a statement that the accord "recognizes the aspirations of the people of Ukraine to live in a country governed by values, by democracy and the rule of law".

The move comes hours after the EU broadened its sanctions over Russia's annexation of Crimea. It added 12 individuals to an earlier list of 21 who now face asset freezes and travel bans.

The U.S. on Thursday added to its own list and also targeted the Rossiya bank.

Russian Foreign Minister Sergei Lavrov said on Friday the international sanctions were "absolutely unlawful".

However, President Vladimir Putin said after talks with officials in Moscow that Russia would not take an immediate reciprocal action. "I think we should refrain from taking steps in response for now," Interfax quoted Putin as saying.

However, Russian Prime Minister Dmitry Medvedev said Ukraine should pay back $11bn in gas discounts as an agreement linked to the lease of the Sevastopol naval base in Crimea was now invalid.

Two credit rating agencies have now downgraded Russia's outlook to negative from stable.

In Moscow, all 155 senators present in the upper house of parliament voted to ratify the treaty incorporating Crimea into the Russian Federation.

Putin is expected to complete the process by signing the treaty at a ceremony later on Friday.