The first funerals of victims in Sunday’s suicide bombing in the Russian city of Volgograd are to take place as shocked residents are still dealing with Monday’s blast on a trolleybus.

The deaths of at least 33 people in just 24-hours have sparked a massive security operation with more than 4,000 police and interior troops deployed.

Fear and grief turned to anger at a gathering to remember the victims.

Organiser Mikhail Yasin said the security forces have failed to protect people and were only good at detaining the innocent.

He added: “Russian citizens should put a question to the authorities, not only about the legitimacy of our law enforcement bodies, but about the necessity of their existence in their current state. It’s about time the whole anti-terror and law enforcement system was reformed.”

Fears of an Islamist terror campaign in the run up to the Winter Olympics in Sochi have spread to the capital Moscow.

President Putin has called for international solidarity in the fight against terror but that is little comfort to those who feel they are now on the front line.

“Inside I feel very anxious especially when I drive,” said a Moscow trolleybus driver. “I am very cautious. Now I look at the passengers and examine them. We also check the trolleybus.”

CCTV footage of Sunday’s train station suicide bombing has revealed two possible suspects in the entrance hall.

Militants from the nearby Caucasus republics of Chechnya and Dagestan have been blamed.