Zimbabwe police manned checkpoints on many main roads on Saturday, searching vehicles for protesters allegedly involved in recent anti-government demonstrations.
A crackdown by security forces has been fiercely criticised by the UN human rights office, with allegations of shootings, beatings and abductions of opposition figures, activists and ordinary residents.
Police roadblocks were a notorious feature of daily life under former president Robert Mugabe.
But they largely disappeared after he was ousted by the military in November 2017 and succeeded by his former deputy Emmerson Mnangagwa.
"We want to tell members of the public that... we have already set up security checkpoints where police officers and other security institutions will be checking," police spokeswoman Charity Charamba told Saturday's state-owned Herald newspaper.
She said the checkpoints were to catch suspected looters and recover property stolen during protests that erupted after Mnangagwa last weekend announced a 150-percent increase in petrol prices.
The Herald said 700 people had been arrested after the violent protests, which it blamed on the opposition MDC party and trade unions.
- Police armed with assault rifles -
Police checkpoints were in action on Saturday in the capital Harare and the second city Bulawayo, AFP reporters witnessed.
In Bulawayo, police officers armed with assault rifles manned roadblocks on every major route, conducting "stop and search" operations.
In both cities, customers seeking to stock up on basic goods tentatively returned to shops that opened for the first time since the protests started on Monday.
Long queues formed to buy bread and petrol, which are both in short supply due to Zimbabwe's long-burning economic crisis.
"Nothing has changed after the fuel price increase," said one motorist in a queue who identified himself only as Sonny.
Social media has been blocked by the government in an apparent attempt to suppress information about the security operation and alleged abuses.
The Zimbabwe Human Rights NGO Forum said it had recorded at least 12 deaths, 78 gunshot injuries and more than 240 incidents of assault and torture.
The United Nations human rights office on Friday urged Harare to "stop the crackdown", voicing alarm over the security forces' "excessive use of force" which included reports of them using live ammunition.
And it called on Zimbabwe's government "to find ways of engaging with the population about their legitimate grievances".