KYIV — At least six people have been killed and more than a dozen injured in a Russian missile attack on Kharkiv, north-eastern Ukraine, according to the regional head.

A further two people remain missing after the attack, which saw Russian forces strike Ukraine's second-largest city at least 15 times, Oleg Sinegubov said.

He advised people in the city to remain in shelters.

Ukraine's state railway company said several of its facilities had been damaged in the attack and a number of its employees had been injured.

Earlier this month, Russian forces began a renewed offensive in the region in an attempt to break through a weakened Ukrainian front line.

On Wednesday, Sinegubov said fighting was continuing near the towns of Pletenivka and Vovchansk, but that Ukraine's forces were in control.

"This weakness is not ours, but the world's, which has not dared to deal with terrorists in the way they deserve for three years," he said in a post on X.

Ukrainian President Volodymyr Zelensky said the attacks on Kharkiv showed that Russia was taking advantage of Ukraine's lack of air defenses.

Supplies of US-made surface-to-air missile systems were delayed by wrangling in Congress over a multi-billion dollar aid package for Ukraine which was only passed last month.

Zelensky has repeatedly called for more air defense missiles and the supply of modern fighter jets from his allies.

Russia's glide bombs devastating Ukraine's cities on the cheap

Thousands flee Russian offensive in Kharkiv region

Ukraine's defense lines stretched as Russian troops advance

Fighting in the region has displaced around 14,000 people, according to the World Health Organization (WHO).

The estimated 189,000 people who remain near the border with Russia face “significant risks due to ongoing fighting”, WHO’s Jarno Habicht said.

Russia's President Vladimir Putin claims it is not his intention to capture Kharkiv, but that the aim was to create a "security zone" for Russia's border region.

Ukraine has been launching its own attacks into Russian territory.

Belgorod, located just 12km (7 miles) from the border with Ukraine, has been targeted a number of times, including earlier this week when a woman was killed and three others were injured as a result of a drone strike on a moving car.

Zelensky warned last week that the Russian ground offensive may only be a "first wave". — BBC