(Recasts with more quotes by Austin, Milley)
By Idrees Ali and Sabine Siebold
RAMSTEIN AIR BASE, Germany, Sept 8 (Reuters) - Ukraine is using its modern Western weapons to devastating effect, striking hundred of Russian targets with the U.S.-supplied HIMARS rocket system alone, General Mark Milley, the Chairman of the U.S. Joint Chiefs of Staff, said on Thursday.
"We are seeing real and measurable gains from Ukraine in the use of these systems. For example, the Ukrainians have struck over 400 targets with the HIMARS and they've had devastating effect," Milley told reporters after a meeting of dozens of defence ministers at Ramstein air base in Germany.
The ministers met to discuss how to support Kyiv with military aid over the long haul as the six-month-old conflict, which has killed thousands and reduced Ukrainian cities to rubble, has settled into a war of attrition fought primarily in eastern and southern Ukraine.
U.S. President Joe Biden approved an additional $675 million weapons package for Ukraine, U.S. Defense Secretary Lloyd Austin told the meeting.
The latest U.S. package includes more ammunition, humvees and anti-tank systems.
Washington has already provided more than $10 billion in military assistance to President Volodymyr Zelenskiy's government since Russian troops invaded on Feb. 24.
"This contact group needs to position itself to sustain Ukraine's brave defenders for the long haul," Austin said, referring to the meeting. "That means a continued and determined flow of capability now."
Separately, U.S. Secretary of State Antony Blinken will announce $2 billion in new U.S. military financing to Ukraine and 18 other countries at risk of future Russian aggression, a senior State Department official said.
'DELIBERATE OFFENSIVE OPERATION'
Ukraine has been carrying out a counteroffensive in the south, though details about it are sparse.
"I would characterise it as a very deliberate offensive operation that is calibrated to set conditions and then seize their objectives," Milley said, speaking of steady progress the Ukrainians had been making.
"I don't think they are particularly overstretched per se," he added.
U.S. officials say they are aware that Russia is hoping that Western unity will be tested in the coming months with European countries squeezed by reduced supplies of Russian natural gas and the upcoming November mid-term elections in the United States.
Control of the U.S. Congress is at stake in November's mid-term elections, along with Biden's remaining policy agenda. Those advocating for Ukraine are concerned that Washington's attention may turn to domestic issues as November nears and voters may be more driven by issues closer to home such as the economy.