President Kassym-Jomart Tokayev signed the order "to ensure public safety, restore law and order, protect the rights and freedoms of citizens", according to the Zakon.kz news site.

Hours later, Mr Tokayev said he had taken over as head of the powerful Security Council from veteran former leader
Nursultan Nazarbayev, the former all-powerful president, who resigned in 2019 but retained considerable influence.

Earlier, protesters in Almaty, the former capital, were reported to have set fire to the city administration building, with flames seen coming from windows.

Meanwhile, thousands of others massed outside the presidential residence in the city and a fire was reported at the city prosecutor's office.

The demonstrations erupted after a cap on energy prices was removed, doubling the cost to Kazakhs of liquified petroleum gas which many use to power their cars from 50 tenge (10p) a litre.

The government justified the change by saying the previous set price was unsustainable.

In Almaty, the former Soviet republic's biggest city, police used tear gas and stun grenades to drive hundreds of protesters out of the main square.

Clashes went on for hours late into the night on Tuesday in nearby areas and a state of emergency was declared - including a curfew, restrictions on movement, and a ban on mass gatherings.

Another state of emergency was declared in the western Mangistau province, where much of the country's rich oil reserves are extracted and which was also the scene of mass protests.

On Wednesday morning (around 3am UK time) President Tokayev accepted his government's resignation.

As he did so, he ordered the government to regulate prices of fuel and other "socially important" goods, rolling back on the gas price hike which triggered the violent protests.

But in the hours after, protesters armed with clubs and metal bars stormed into the mayor's office of Almaty.

Videos posted online showed a large crowd outside the concrete administration building, as smoke billowed out of a number of rooms and stun grenade explosions could be heard.

Protesters appeared to break through the security forces' cordons despite the use of the stun grenades, and gunfire and explosions could be heard throughout the city centre.

The local police chief claimed "extremists" were attacking Almaty, and had "beaten up 500 civilians".

The police were joined by units from the National Guard and army as they attempted to bring order to the city.

There were also unconfirmed social media reports that civilians were detaining security personnel and workers in some industries were striking.

Amid reports of strikes at Kazakhstan's oil fields, one supplier, Tengizchevroil, told Sky News: "Tengizchevroil (TCO) has been notified that a number of contractor employees have gathered at the Tengiz field in support of meetings taking place in Mangistau oblast. TCO and Business Partner Industrial Relations teams are working together to resolve this situation as soon as possible. This incident has not impacted TCO production operations."

Shortly after the police chief's statement, Zakon.kz became unavailable and internet watchers reported that there had been a mass outage on Kazakhstan's internet services, with netblocks.org tweeting: "Confirmed: #Kazakhstan is now in the midst of a nation-scale internet blackout after a day of mobile internet disruptions and partial restrictions".

Kremlin spokesman Dmitry Peskov in Moscow said it was important that Kazakhstan solved its own problems and that no one should interfere from outside.

At around the same time a Russian news site, Lente.ru, reported that a Russian military Il-76 transport plane, of the type usually used for moving supplies and people, had landed in Almaty, citing the Flight Radar open source air traffic monitor.

The state of emergency decree said that, up until midnight on 19 January, there would be an overnight curfew, restrictions on movement, including of vehicles, into, out of and within Nur-Sultan, and a ban on gatherings and strikes.

Kazakhstan was under one-man rule by former leader Nursultan Nazarbayev for three decades, until he stood down, helping it attract hundreds of billions of dollars of foreign investment in its oil and metals industries.

About a fifth of Islam-majority Kazakhstan's population are Russians, the descendants of those who moved there in Soviet era.