Police officers were seen outside the Parliament building in Tunis on March 18, 2015. Young demonstrators gathered outside the municipal theater protesting acts of terrorism in their country. Reuters

Groups of Tunisians took to the streets in the capital city Wednesday, objecting to terrorism in the North African country following a deadly attack staged by gunmen at a museum in the Parliament compound earlier in the day. Some world leaders responded by showing support for the people of Tunisia and expressing their condolences over the loss of at least 20 lives.

Many demonstrators gathered outside the municipal theater on Avenue Bourguiba, in the center of Tunis, in a show of solidarity after the attack, chanting, "Tunisia is free, terrorism out," according to the BBC. Eric Reidy, a journalist who has written about the Middle East for Al Jazeera, reported that people were singing the Tunisian national anthem during the protest.

“We commend Tunisian authorities’ rapid response to today’s wanton violence and their efforts to resolve the hostage situation and restore calm,” U.S. Secretary of State John Kerry said in a news release. “The United States stands with the Tunisian people at this difficult time and continues to support the Tunisian government’s efforts to advance a secure, prosperous, and democratic Tunisia.” U.S. Department of State spokeswoman Jen Psaki said during the agency’s daily news briefing Wednesday that she was not aware of any U.S. citizens being among those killed in the museum attack, and that the U.S. Embassy in Tunisia, which is about 10 miles from where the attack was staged, will remain open.

President Donald Tusk of the European Council and Secretary-General Ban Ki-moon of the United Nations have also joined in the condemnation of the attacks with various tweets and statements released to the media. French President Francois Hollande also tweeted a statement that was translated in part as saying "Every time a terrorist crime is committed, anywhere, we are all concerned."

Five militants were involved in the attack at the Bardo Museum, which is located inside the Parliament compound in Tunis. Two of the attackers were killed by security forces while the other three remain at large. The attackers ducked into the museum, holding some 30 people hostage. According to Tunisian Prime Minister Habib Essid, at least 20 people were killed in the attack, including 17 foreign tourists from Germany, Poland, Italy and Spain, and more than 20 people suffered injuries.

The affiliations of the assailants were not known yet, but European Union foreign policy chief Federica Mogherini blamed the Islamic State group for the attack, according to the BBC. Sebastian Usher, the BBC's Arab affairs editor, said the gunmen were likely Islamic militants trying to derail Tunisia's democratic transition. The country has been fighting Islamist militants who emerged after 2011’s so-called Arab Spring uprising.