A human rights worker was hospitalized after being beaten up in his apartment building, an attack his employer said was linked to his work. Bakhrom Khamroyev, a member of leading human rights group Memorial, was walking into the building in southeast Moscow on Monday when a group of strangers attacked him, spraying gas in his face and beating him on the head and legs. Memorial chief Oleg Orlov said Tuesday that the attack was aimed at disrupting Khamroyev's upcoming trip to Murmansk, where he had arranged a meeting with an Uzbek citizen threatened with extradition for purportedly taking part in Islamist militant activities, RIA-Novosti reported. "Memorial believes the attack on Bakhrom Khamroyev was planned in advance and prepared as a trap," Memorial said in a statement. "In December last year, an attack was carried out on Khamroyev. A criminal case was opened, but until today no one has been called to take responsibility." Orlov said Khamroyev was attacked by security forces in December when he was working on a similar case involving the arrest of suspected militants from Central Asia. The head of Amnesty International's Russia division, Sergei Nikitin, called on authorities to find and punish those responsible for the beating. "We hope a serious investigation will be carried out and that the guilty are punished," he said. Police said Tuesday that they were looking for the attackers.