Moscow is observing a day of mourning on Wednesday for the victims of the January 24 terrorist attack on the capital’s Domodedovo airport, according to RIA Novosti.

Flags will be at half mast across Moscow and the surrounding region and TV companies have been advised by the mayor’s office to cancel all entertainment programs as a sign of respect.

Monday’s blast at the airport arrivals zone claimed the lives of 35 people and left scores injured. No group has yet taken responsibility for the attack, which comes less than 12 months after two female suicide bombers from the volatile North Caucasus struck the Moscow metro, killing dozens.

The identity of the terrorist or terrorists who carried out the blast has not yet been officially confirmed, with conflicting reports suggesting the attack was carried out by a female Black Widow suicide bomber accompanied by a man, or a man on his own.

Prime Minister Vladimir Putin, who declined to comment on the attack in the initial aftermath of the blast, has said that “retribution is inevitable.”

President Dmitry Medvedev earlier criticized security at the airport and said those responsible would be “punished.”