The exchange of ideas and experiences during the exercise helps build trust, build up security and stability in Central Asia, observers say.
Tajik and foreign troops are learning from each other in Exercise Regional Co-operation 2017.
Five state agencies work together to block illegal content online as well as seize printed materials with radical views.
EU intends to strengthen co-operation with Central Asian states to fight terrorism and increase border security, EU representatives to Kyrgyzstan say.
Tajikistan will host the annual multi-national Exercise Regional Co-operation in July.
New economic projects will reduce the sway of extremist messages in Uzbekistan's Fergana Valley provinces, hope officials.
Kazakhstan is taking a leading role against extremism and terrorism, say analysts and officials.
The EU, by organising discussions, will help Kyrgyzstan "make the public more resistant to radicalisation and extremist propaganda", say EU officials.
The government developed regulations for schools and universities across the country.
Kazakhstan will install anti-ram vehicle barriers and a facial recognition system to guard the Astana event, say officials.