Russia-Ukraine updates: Russian missiles hit close to nuclear reactors: IAEA director

U.S. officials do not know who to blame for the car bomb that killed the daughter of political theorist Alexander Dugin, a close ally of Russian President Vladimir Putin, Rep. Adam Schiff, the Democratic chair of the House Intelligence Committee, said during an interview Sunday on CNN’s "State of the Union."

Daria Dugina, a 29-year-old TV commentator, was killed on the Mozhaisk Highway in the outskirts of Moscow on Saturday night by an explosive that had been planted in the Toyota Land Cruiser she was driving, Russia's state-run news agency TASS reported.

Alexander Dugin, often referred to as "Putin’s brain," had just attended "Tradition" cultural festival with his daughter, according to TASS. Russian media outlets reported that the SUV belonged to Dugin.

The Russian Investigative Committee press office told TASS Dugina's killing was planned and contracted.

Schiff said Sunday that he had not yet been briefed on the killing and that he "couldn’t say" who is behind it, adding that he hoped it was an "internal Russian affair" rather than something “emanating from Ukraine.”

"There are so many factions and internecine warfare within Russian society, within the Russian government," Schiff said. "Anything is possible."

Adviser to the Ukrainian presidential office Mikhail Podolyak denied Kyiv was involved in the explosion that killed Dugina during a televised interview on Sunday.

"I emphasize that Ukraine certainly has nothing to do with this, because we are not a criminal state like the Russian Federation, and even less a terrorist state," Podolyak said.

-ABC News' Ben Gittleson and Patrick Reevell

Videos circulating online show smoke rising over Sevastopol, the largest city in Crimea and a major port on the Black Sea.

The city's Russian-appointed governor said a drone was struck down and fell through the roof of Russia's Black Sea Fleet Headquarters. Ukraine has not commented on the strike.

-ABC News' Layla Ferris

The U.S. has authorized a new $775 million military aid package for Ukraine, the Department of Defense announced on Friday.

The package will include more High Mobility Artillery Rocket System (HIMARS) ammunition and howitzers, as well as some firsts, including ScanEagle reconnaissance drones and Mine Resistant Ambush Protected (MRAP) vehicles.

The 15 ScanEagle drones are intended to help Ukraine identify targets and put the HIMARS and howitzers to better use, according to a senior U.S. defense official.

The 40 MRAP vehicles and other mine-clearing equipment will help Ukrainian troops cross dangerous terrain, according to the official.

"We know that Russia has heavily mined areas in parts of southern and eastern Ukraine. We know there's a significant amount of unexploded ordinance," the official said.

The new aid package follows a $1 billion package announced on Aug. 8.

-ABC News' Matthew Seyler

A major pipeline that supplies natural gas from Russia to Europe will be shut down for three days for maintenance, Russian energy corporation Gazprom said Friday.

Gas supplies via the Nord Stream pipeline will be suspended from Aug. 31 to Sept. 2 for "servicing and preventive maintenance" of its only operative gas compressor unit, Gazprom said.

Gas transmission is scheduled to resume after that period, barring any malfunctions, at a below-capacity rate of 33 million cubic meters per day, the company said.

The flow of gas via the pipeline has been reduced, and both Nord Stream pipelines were shut down for 10 days last month for maintenance, as Europe faces an energy crisis.