At the request of Norwegian police, the Norwegian Home Guard, a rapid mobilisation force, began to deploy troops at plants responsible for processing and exporting oil and gas.

The disengagement comes ahead of a meeting in Uzbekistan that Chinese President Xi Jinping and Indian Prime Minister Narendra Modi are expected to attend.

Reprisals carried on late into the night and through the next day, with mobs setting alight dozens of homes belonging to ruling-party politicians around the country.

Rajapaksa's evacuation to an undisclosed location followed a day of violent protests in which five people, including a lawmaker, were killed and nearly 200 wounded.

Moscow had previously admitted to losses but without giving any numbers.

The new deployments include reconnaissance and artillery troops and medics from units throughout Germany, as well as around 100 howitzer and other vehicles, with arrivals expected to continue throughout this week.

Russia is holding joint military exercises in ex-Soviet Belarus as well as naval drills in the Black Sea, part of a surge of military activity near Ukraine that has fuelled fears of an impending invasion. Russia denies any plans to attack.

Russian President Vladimir Putin has claimed victory in defending Kazakhstan from what he described as a foreign-backed terrorist uprising.

Seventy-two people have died and more than 1,200 people arrested since former president Jacob Zuma began a 15-month jail term, sparking protests that swiftly turned violent.

Pentagon spokesman John Kirby says the September deadline remains in place although the pace can be adjusted based on conditions.

Pentagon spokesman says some of the Patriot anti-missile batteries are being redeployed to other countries and some are returning to the US for maintenance.