Please, check if the following passage is grammatically correct. Thanks!
(Partia = a fictitious name of a country)
Partia maintains ties with radical groups around the world. These groups serve as "sleeper cells" for Partia, awaiting its order. Partia's diplomatic mail bags are used for transferring weaponry to these cells, since diplomatic bags are not subjected to security check in the host countries' airports. Moreover, Partia's embassies worldwide serve as depots of weapons, ammunition and explosives, as well as bases of intelligence and operation of agents and collaborators. Putting these embassies and their diplomats under surveillance, may provide the host country's security services with much information on subversive activity inside the country.