Russian-led forces have arrived in Kazakhstan at the request of the country"s authoritarian president, amid a violent crackdown on anti-government protests, BBC reported. Officials have reported deaths of police and protesters after days of unrest sparked by a fuel price hike. A BBC journalist in the largest city Almaty shared video of heavy gunfire overnight on Thursday. The UN, US, UK, and France have called on all sides to refrain from violence. In Jeddah, the Organization of Islamic Cooperation (OIC) called for restraint and ceasing of violence to overcome the current crisis in Kazakhstan. President Kassym-Jomart Tokayev has blamed foreign-trained "terrorists" for the unrest, without giving evidence. In an address on state TV on Wednesday, he appealed to the Russian-led Collective Security Treaty Organisation (CSTO) for support. The bloc includes Russia, Kazakhstan, Belarus, Tajikistan and Armenia. The overseas force being sent to Kazakhstan reportedly numbers about 2,500 soldiers. The CSTO says the troops are a peacekeeping force and will protect state and military installations. They will stay in the country for several days or weeks, the Russian RIA news agency reports. The US State Department has said it is closely monitoring the deployment of Russian troops. "The United States and, frankly, the world will be watching for any violation of human rights," a spokesman said. "We will also be watching for any actions that may lay the predicate for the seizure of Kazakh institutions." The OIC General Secretariat expressed regret over the violent incidents that led to the deaths of many people and the destruction of public property. The OIC followed up with great concern the developments of the situation in Kazakhstan, calling for maximum restraint and calm, renunciation of violence, safeguarding the national interest and placing it above all considerations to overcome the current crisis, a statement carried by the Saudi Press Agency said. The organization"s General Secretariat affirmed its full solidarity with the government of Kazakhstan in preserving its sovereignty, security, stability and territorial integrity and the national unity of the country. Some 18 members of the security forces have died in Almaty, officials said, and police said they had killed dozens of people described as "rioters" overnight on Wednesday. Saule, a 58-year-old construction worker who took part in the protests, told AFP news agency that she saw security forces open fire on demonstrators. "We saw the deaths," she said. "Straight away about 10 were killed." Kazakhstan"s interior ministry says 2,298 protesters have also been detained. The unrest began on Sunday when the cost of liquefied petroleum gas (LPG) - which many people in Kazakhstan use to fuel their cars - doubled, drawing protesters onto the streets. The government said on Thursday that fuel price caps will be restored for six months. But the announcement has failed to end the protests, which have broadened to include other political grievances. Kazakhstan is often described as authoritarian, and most elections are won by the ruling party with nearly 100% of the vote. There is no effective political opposition. A presidential residence in Almaty and its mayor"s office were both ablaze on Thursday. The military has now regained control of the main airport, which had been seized by protesters. Kazakhstan"s health ministry said about 1,000 people have been injured in the unrest. The bloodshed comes after President Tokayev sacked his cabinet on Wednesday in a bid to head off the demonstrations. He also fired his powerful predecessor, Nursultan Nazarbayev, who had held a national security role since stepping down as president. — Agencies