A rocket attack on Ukraine's military headquarters in the war-torn east has killed at least six civilians, officials said.
At least 26 people, including ten service personnel, were wounded in the attack.
President Petro Poroshenko said that rockets from a Tornado multiple launch system hit the command centre in Kramatorsk, a town behind the frontlines which is considered to be under firm government control.
Local officials said the strikes killed at least six people and wounded 21 in nearby residential areas.
Ukrainian foreign ministry official Dmytro Kuleba tweeted that the rockets were Tornado, "Russia's newest Multiple Launch Rocket System. Ukraine simply doesn't have it."
Ukraine accuses Russia of supplying and training heavily armed separatists, but Russia denies this.
Pro-Russian separatists say their weapons have been captured from Ukrainian forces, although Kiev has cited numerous cases of rebels deploying advanced weapons that are only available from Russian arsenals.
Kramatorsk was recaptured by government forces from rebels in June and made the regional capital of Ukrainian-controlled territory.
The rocket strike came as separatist forces pushed an offensive to take territory ahead of a planned peace summit in Minsk tomorrow.
The closest rebel position to Kramatorsk is believed to be Gorlivka, around 45km to the southeast - well within the range of the Tornado rocket.
Ukraine town destroyed in rebel offensive
The Ukrainian security council has said an offensive has been launched against separatists near the strategic southeastern port of Mariupol.
Seven Ukrainian soldiers have been killed and 23 wounded in fighting with separatists in Ukraine's eastern regions in the past 24 hours, the military said.
A spokesman said government forces had come under attack from separatists on 87 separate occasions since yesterday.
Fighting is reported to be particularly intense around the town of Debaltseve, a major rail and road junction northeast of the city of Donetsk.
Meanwhile, talks on how to resolve the crisis are expected to focus on withdrawing heavy weapons, creating a demilitarised zone and starting a dialogue between government and rebel forces.
France, Germany, Russia and Ukraine are due to meet tomorrow in the Belarusian capital of Minsk.
The issue of who will oversee the proposed demilitarised zone is viewed as a sticking point, with EU security watchdog the OSCE the prefer choice of Russia, while France and Germany want Russia to oversee it.
Earlier, a Russian government spokesperson said Western plans to send weapons to Ukraine and to extend sanctions are steps aimed at destabilising the situation.
Describing the West's position towards Russia as regrettable, Dmitry Peskov said Russia is interested in solving the crisis.
Nikolai Patrushev, head of the Kremlin's Security Council, has said that if the US sends weapons to Ukraine, Russia will most likely respond diplomatically.
In Russia, the Interfax news agency is reporting that about 2,000 Russian reconnaissance troops have started exercises in southern Russia.
A further 600 troops have begun exercises in Crimea, along with 50 units of weaponry, according to a spokesperson for Russia's Black Sea fleet.
Meanwhile, Ukraine's parliament voted to approve President Poroshenko's proposal to dismiss General Prosecutor Vitaliy Yarema.
Deputies, activists and the country's Western backers have regularly accused the prosecutor's office of failing to tackle corruption and roll out reforms.
