U.S. and European Union (EU) leaders have unveiled new sanctions on Russia for its military operations in Ukraine. However, experts say the move would not have an immediate impact. 

EU leaders wrapped up an emergency summit early Friday with an agreement to impose sanctions on Russia's banking, energy and technology sectors. 

The U.S. said on Thursday it was implementing export controls that will severely restrict Russia's access to technologies that it needs to sustain its military capabilities. 

Even though the latest rounds of sanctions are bigger in size and scope than the previous ones, they will not have a direct and immediate impact on Russia's military actions in Ukraine, Zhang Xin, an associate professor at the School of Politics and International Relations of East China Normal University, told CGTN. 

The U.S. officials previously suggested that the threat of sanctions was intended to deter Russian troops from entering Ukraine. But U.S. President Joe Biden said on Thursday that the sanctions were designed to maximize the long-term impact on Russia. 

"No one expected the sanctions to prevent anything from happening," Biden said while adding that "this is going to take time." 

Brian O'Toole, former director of the U.S. Office of Foreign Assets Control, told NBC that sanctions may take years to hurt the Russian economy. 

"The tool of sanctions has become a tired tool," Stephen Biegun, former U.S. deputy secretary of state, told Bloomberg. 

Biegun added that the use of sanctions "has not seemed to significantly alter the behavior of any foreign party whose actions are of concern to the United States." 

The U.S. has imposed more than 100 sanctions on Russia since 2011, but this is not a fundamental and effective means to solve the problem, the Chinese Foreign Ministry said on Friday.  

The United States and Britain announced restrictions that, combined with previous sanctions, would effectively kick the vast majority of Russian banking assets out of both countries. New targets include Sberbank and VTB Bank, Russia's two largest lenders. 

The EU sanctions on Russia's energy sector include an export ban on equipment and technology that Russia needs to upgrade its oil refineries, as well as a ban on aircraft and aviation parts to its airlines.

(With input from agencies)