Despite the need for blood in Orlando, Florida, after the worst mass shooting in the United States' history, the Food and Drug Administration’s rules that do not permit gay or bisexual men to donate blood if they have had sex with another man in the past 12 months, remain in place, CNN reported. This is regardless of the fact that the bloodshed, which killed 49 and injured 53 others, took place at a gay bar.

Orlando’s OneBlood donation centre took to Twitter to appeal for blood donations soon after the shooting. Its plea received an overwhelming response from citizens who rushed to do their bit, lining up in queues of hundreds to donate. At one point, media reports had suggested that the ban on blood donations from gay men had been lifted, but OneBlood clarified on Twitter that the reports were false and that the rules remained in place, CNN reported.

While the FDA had earlier imposed a lifetime ban on accepting donations from men who have had sex with men, it updated its rules on the matter in 2015. That lifetime ban was enforced in 1992 when the AIDS epidemic worsened.

A gunman, identified as 29-year-old Omar Mateen, opened fire inside Orlando’s Pulse nightclub late on Saturday. Before the attack, the assailant had pledged allegiance to the Islamic State. Mateen had reportedly called emergency line 911 and said he was allied with the extremist group.