NEW YORK - Jewish groups in the US have expressed shock and horror following the shooting at a gay nightclub in Orlando, Florida, described as the deadliest mass shooting in US history. The Jewish Federation of Greater Orlando extended “deepest sympathy” to those affected on Sunday. “The Jewish community has been impacted many times by terror attacks, and we stand united in denouncing all violence,” the Federation wrote on its website. “We are in close touch with local, federal and state authorities, and we have full faith and confidence in our law enforcement.” They also called on the public to remain vigilant and alert authorities immediately about any suspicious activity witnessed. The Anti-Defamation league also expressed “shock and horror”. According to the group’s CEO Jonathan A. Greenblatt the “heinous” attack is “yet another reminder of the serious threat posed by the Islamic State terrorist group.”He described the shooting as a “barbaric act of terrorism in a week that has seen brutal bombings across Iraq, an attack on a cafe in Tel Aviv, and now this tragedy.”“We must continue to fight this threat against democracy and pluralism with all of the tools available and by exposing those who perpetrate hateful ideologies of violence and extremism,” Greenblatt said. The ADL also expressed concern that the Orlando attack could lead to a backlash against American Muslims. “Whether citizens like the individual suspected of committing this act or war-torn refugees seeking safety, we must remember that we do not define people by their faith,” Greenblatt stressed. “We urge all Americans to not fight hatred with hatred, but rather to come together around our common values of decency and respect.”CEO of The American Jewish Committee David Harris added that AJC is "simply speechless in the face of such an act of pure evil and hatred.” "This is a time for national solidarity and mourning," Harris added. "Violence and hate crimes must be totally and categorically rejected.” Raising the endless debate on gun control, he also asked: “How can weapons be so easily found and used to such tragic ends in our beloved country?” Groups advocating for tougher gun control in the United States have yet again called for change on this issue, as they do each time a shooting occurs.The statewide advocacy group New Yorkers Against Gun Violence stressed on Sunday that “any shooting, whether it is deemed a mass shooting or not, is an act of terrorism to the person being shot, to their friends and family, and to their communities.”They added that the weapon used in the Orlando attack, an AR-15 assault rifle with a high capacity ammunition magazine is an arm designed by the military for the military, “yet they have been used time after time to slaughter Americans in our schools, houses of worship, movie theaters, malls and night clubs.”“We make it far too easy for angry, hate-filled individuals to legally obtain these highly lethal weapons,” NYAGV wrote. “We are sick and tired of writing these statements.”The organization called on the public to contact legislators and ask them to renew and strengthen the 1994 US ban on military-style assault weapons and high capacity ammunition magazines that expired in 2004, and impose background checks on all firearms purchasers, including those on the Terrorist Watch List.