WRAPUP 7-Russia prepares for next Ukraine offensive in face of new Western weapons

* Russia shelling 'along the entire front line' - Ukraine military

* Russia regrouping for offensive toward Sloviansk, Kyiv says

* Moscow orders steps to prevent Ukrainian strikes in east

* Zelenskiy fires top officials

By Tom Balmforth and Max Hunder

KYIV, July 17 (Reuters) - Russia is preparing for the next stage of its offensive in Ukraine, a Ukrainian military official said, after Moscow said its forces would step up military operations in "all operational areas".

As Western deliveries of long-range arms begin to help Ukraine on the battlefield, Russian rockets and missiles have pounded cities in strikes that Kyiv says have killed dozens in recent days.

"It is not only missile strikes from the air and sea," Vadym Skibitskyi, a spokesman for Ukrainian military intelligence, said late on Saturday. "We can see shelling along the entire line of contact, along the entire front line. There is an active use of tactical aviation and attack helicopters.

"Clearly preparations are now underway for the next stage of the offensive."

The Ukrainian military said Russia appeared to be regrouping units for an offensive toward Sloviansk, a symbolically important city held by Ukraine in the eastern region of Donetsk.

The British defence ministry said on Sunday that Russia was also reinforcing defences across areas it occupies in southern Ukraine after pressure from Ukrainian forces and pledges from Ukrainian leaders to drive Russia out.

Ukraine says at least 40 people have been killed in Russian shelling of urban areas since Thursday as the war launched by Russian President Vladimir Putin on Feb. 24 intensifies.

Dozens of relatives and local residents attended the funeral of four-year-old Liza Dmytrieva in the central Ukrainian city of Vinnytsia on Sunday. The girl was killed in a missile strike on central Vinnytsia on Thursday that killed 24 people, according to Ukrainian authorities.

To the south, more than 50 Russian Grad rockets pounded the city of Nikopol on the Dnipro River, killing two people who were found in the rubble, Governor Valentyn Reznichenko said.

Ukrainian President Volodymyr Zelenskiy said Russia had used more than 3,000 cruise missiles to date and it was "impossible to count" the number of artillery and other strikes so far.

ZELENSKIY FIRES TOP OFFICIALS

Meanwhile, Zelenskiy fired the head of Ukraine's powerful domestic security agency, Ivan Bakanov, and Prosecutor General Iryna Venediktova, who led the effort to prosecute Russian war crimes, saying many of their employees were collaborating with Russia.