The police and South African National Defence Force arrested 28 people yesterday and seized firearms, ammunition and 150kg of dagga from three hostels.
The search was conducted at the Wolhuter and George Goch hostels in Jeppe and the Denver hostel in Cleveland at 1am.
This follows 11 days of xenophobic attacks in Gauteng, in which 42 people were killed and thousands displaced.
President Thabo Mbeki gave the go-ahead on Wednesday for the army to help quell the violence.
Police stations and church buildings have been turned into safe havens for foreigners fleeing the xenophobic violence.
Police spokesman Sally de Beer said yesterday that army personnel would only be deployed when the police required their assistance.
"This was the only joint operation yesterday," De Beer said.
The 21 South African Infantry Battalion formed outer security rings while the police entered the premises and carried out search, seizure and arrest duties.
"The SAPS and SANDF will work together until calm is restored in Gauteng," she said.