Britain on Friday summoned Iran's most senior diplomat in London to protest the hanging of Mohsen Shekari, the first such execution over ongoing anti-government unrest. "The execution of Mohsen Shekari by the Iranian regime is abhorrent. He is a tragic victim of a legal system in which disproportionate sentences, politically motivated trials, and forced confessions are rife," Foreign Secretary James Cleverly said in a statement. "We have made our views clear to the Iranian authorities – Iran must immediately halt executions and end the violence against its own people," Cleverly added. Germany on Friday condemned Iran's execution of a man over recent anti-government unrest, called on Tehran to immediately end its violence against protesters, and confirmed it had summoned the Iranian ambassador in Berlin. "The German government strongly condemns the Iranian regime's death sentence and execution of a demonstrator in connection with the demonstrations in Iran," a government spokesperson told a news conference in Berlin. The European Union is preparing to add 20 people and an Iranian entity to its blacklist over human rights violations committed in Iran during the repression of demonstrations, diplomatic sources in Brussels said on Friday. Amnesty International said it was "horrified" by the execution. "His execution exposes the inhumanity of Iran's so-called justice system" where many others face "the same fate", it added. "The international community must immediately and strongly react to this execution," Mahmood Amiry-Moghaddam, director of the Norway-based group Iran Human Rights, said in a statement. "If Mohsen Shekari's execution is not met with serious consequences for the government, we will face mass execution of protesters," he added. Overnight, protesters took to the street where Shekari was arrested, shouting, "They took away our Mohsen and brought back his body," in a video shared by 1500tasvir. Elsewhere, chants of "Death to the dictator" and "Death to Sepah" were heard at a demonstration in Tehran's Chitgar district, in reference to supreme leader Ayatollah Ali Khamenei and Iran's Revolutionary Guards. Hamed Esmaeilion, an Iranian-Canadian activist who has organized mass protests in Berlin, Paris, and other cities, said more demonstrations would be held at the weekend. "Regardless of belief and ideology, let's join these gatherings in protest against the brutal execution of Mohsen Shekari," he tweeted. Nationwide protests erupted after the death of 22-year-old Iranian woman Mahsa Amini on Sept. 16. Iran executed a protester on Thursday who was convicted of injuring a security guard and closing off a street. The Iranian Foreign Ministry said that "in countering riots, Iran's shown utmost restraint and -unlike many Western regimes who smear and violently crackdown even the peaceful protests- Iran has employed proportionate and standard anti-riot methods. The same is true for the judicial process: restraint and proportionality.” "Yet, public security is a redline. Armed assault and vandalism are not tolerable, even to Western regimes who've found an opportunity to hypercritically lecture Iran. Instead of exposing its mendacity by politicized statements, West must stop hosting, backing, and encouraging terrorists," the ministry noted. "Fighting terrorism, violence and hate speech are unequivocal int. responsibilities," Iranian Foreign Minister Hossein Amir-Abdollahian said. "Hypocritical is that Germany considers these as red lines for its territory and security, but incites the same sinister phenomena in Iran and duplicitously denounces our legitimate struggle against them," he added.