Russia-Ukraine updates: Putin suspends key US-Russia nuclear treaty in speech denouncing West

The United States will send another $675 million in assistance to Ukraine amid Russia's war, Secretary of Defense Lloyd Austin announced Thursday.

"Yesterday, President Biden approved the latest tranche of U.S. assistance to Ukraine, valued at up to $675 million, and this is the Biden administration's 20th drawdown of equipment from U.S. stocks for Ukraine since last August," Austin told reporters at the U.S. military's Ramstein Air Base in Germany, where he attended a meeting of the Ukraine Defense Contact Group.

"The latest package includes more GMLRS, 105 millimeter howitzers, artillery ammunition and HARMs, Humvees, armored ambulances, anti-tank systems, small arms and more," he added.

The Ukraine Defence Contact Group is a U.S.-led effort to bring together defense leaders from dozens of countries around the world in order to facilitate military support for Ukraine in its ongoing efforts to fight the Russian invasion. Austin said Thursday that the group was meeting to "renew our commitment and intensify our momentum to support the brave defenders of Ukraine for the long term."

"Today, four months after our initial Contact Group meeting, the war is at another key moment. Russian forces continue to cruelly bombard Ukrainian cities and civilians with missiles and artillery fire," he said. "But Ukrainian forces have begun their counteroffensive in the south of their country."

"This Contact Group needs to position itself to sustain Ukraine's brave defenders for the long haul," he added. "And that means a continued and determined flow of capability now."

Shelling on Tuesday damaged a backup power line at the Zaporizhzhia nuclear power plant in Ukraine, the United Nation's nuclear watchdog said Wednesday.

The International Atomic Energy Agency said there was no immediate impact from the damage because the Russian-held plant was already disconnected from the grid.

The plant previously lost all four of its regular power lines during the conflict, according to the IAEA.

The damaged power line is one of three backup lines between the plant and a nearby thermal power station. The other two are disconnected, the IAEA said.

In recent days, the plant has relied on its sole operating reactor for power, according to the IAEA, which stressed that a "secure off-site power supply from the grid and backup power supply systems are essential for ensuring nuclear safety and preventing a nuclear accident."

-ABC News' Jason Volack

Ukrainian President Volodymyr Zelenskyy claimed during his nightly address Wednesday that several settlements have been recaptured from Russia in the Kharkiv region, though did not provide further details.

"There is good news from the Kharkiv region. However, now is not the time to name the liberated settlements," he said.

-ABC News' Jason Volack and Max Uzol

Ukrainian President Volodymyr Zelenskyy said Tuesday he was the first foreign leader to have a conversation with new United Kingdom Prime Minister Liz Truss.

Zelenskyy said in a statement on social media that he invited her to Ukraine and the two discussed security guarantees and "coordinated further pressure" on Russia.

"The goal is to stop the aggression & bring the perpetrators to justice," he said.

A Downing Street spokeswoman said in a statement that Truss reiterated the U.K.'s "steadfast support" for Ukraine in her first call with a foreign leader since taking office.

“The leaders discussed the need to strengthen global security and the measures necessary to cut off the funds fueling Putin’s war machine," the statement said.

"She praised the Ukrainians' fight for sovereignty and self-determination and said it was essential Ukraine succeeds and Russia fails," the statement continued, adding that Truss was "delighted to accept an invitation to visit President Zelenskyy in Ukraine soon."

-ABC News' Rashid Haddou