The European Union and the United States have called on Belgrade to adhere to democratic principles and human rights standards in response to Serbia's decision to ban certain foreign citizens from entry.
In the past year, Serbia has banned the entry of certain foreign activists, artists, and journalists who Belgrade says are a threat to state security.
Those affected are often from the region, as well as Russian anti-war activists and journalists who publicly criticize the Serbian and Russian authorities.
The most recent case occurred on July 12, when Serbian border police banned Bosnian Nedim Music from entering the country. Music previously supported protests against lithium mining in Serbia and the so-called Jadar project of the company Rio Tinto backed by the Serbian government.
The U.S. State Department on July 18 said that it was aware of Serbia's decisions to ban certain foreign activists.
"Taking into account its status as a candidate country for EU membership and a valued partner in maintaining peace and security throughout the region, we call on Serbia to support the rule of law and the highest democratic standards in these and all other law enforcement actions," the State Department said in an e-mail to RFE/RL.
Serbia became a candidate for EU membership in 2012.
EU spokesman Peter Santo told RFE/RL in an e-mail that the EU was also aware of decisions to ban the entry of various foreign nationals into Serbia but Brussels did not have access to detailed information about the decisions.
Santo said although the state had the right to restrict foreign nationals' access to its territory, it is important that the restrictions are "in accordance with European and international standards on human rights."
Santo said the restrictions "should not result in limiting the freedom of expression and the right to peaceful gathering of foreign citizens."
Decisions on "negative security-risk assessments" are carried out by the Serbian Security and Information Agency.
The Serbian law on foreigners states such security risks exist "if the available data and knowledge indicate that a foreigner advocates, incites, helps, prepares, or undertakes activities that threaten the constitutional order and security of Serbia."
Among those who were recently denied entry into Serbia due to a "negative security-risk assessment" is Bosnian actor and writer Fedja Stukan, known for his participation in mass anti-violence civil protests, and Current Time journalist Roman Perl, who was recently declared a "foreign agent" by Moscow.