- Install a comprehensive network of CCTV cameras and motion sensors in metro stations and on trains.

- Monitor CCTV footage in real time and employ facial recognition technology to identify potential threats.

- Deploy plainclothes security personnel to blend in with passengers and monitor for suspicious activity.

2. Improved access control and security checks

- Install access control systems at station entrances and require passengers to pass through metal detectors and/or baggage scanners before entering the metro system.

- Randomly search passengers and their belongings for weapons or explosives.

3. Increased police presence

- Increase the number of police officers patrolling metro stations and trains, both in uniform and plainclothes.

- Have police officers conduct random checks of passengers' tickets and identification.

4. Emergency preparedness and response

- Develop and implement emergency plans for responding to terrorist attacks, including evacuation procedures and protocols for dealing with hazardous materials.

- Conduct regular drills to ensure that metro personnel are prepared to respond effectively in the event of an attack.

5. Public awareness and education

- Educate the public about the importance of reporting suspicious activity to authorities.

- Encourage passengers to be vigilant and aware of their surroundings when using the metro system.

6. International cooperation and intelligence sharing

- Work closely with law enforcement and intelligence agencies in other countries to share information about potential terrorist threats.

- Participate in international counter-terrorism initiatives and organizations.