Ukrainian drones struck a major refinery deep inside Russia, military officials said Thursday, the fourth in three days in Kyiv's monthslong campaign to choke Moscow's vital oil sector.

Russia is one of the world's biggest energy producers, with oil providing an economic mainstay as its army tries to push deeper into Ukraine in a slow and costly advance more than four years after Moscow launched its full-scale invasion.

Russian President Vladimir Putin on Thursday for the first time visited the Kuril Islands, a Russian-controlled Pacific island chain also claimed by Japan, in a move that drew a protest from Tokyo.

Putin visited a fish plant, a hospital and a school on Iturup, one of the chain's southernmost islands. He also briefly spoke to local residents and met with the governor of Russia's Sakhalin region, Valery Limarenko.

Germany's government plans to give its intelligence services broader powers for actions such as disabling sabotage and hacking attempts in response to a rising threat from powers such as Russia and extremists.

The Cabinet on Wednesday approved draft legislation meant to strengthen Germany's Federal Intelligence Service, the BND, and its domestic intelligence service, the BfV, and reduce the reliance of the European Union's most populous nation on tips from its allies.

North Korea on Wednesday performed its second ballistic missile test in less than a week, its neighbors said, a likely protest of the upcoming South Korea-U.S. military drills that North Korea views as an invasion rehearsal.

South Korea's Joint Chiefs of Staff said a ballistic missile fired from the North's eastern coastal Wonsan area around 6 a.m. flew more than 700 kilometers (435 miles). The Japanese Defense Ministry also detected the launch, saying the weapon landed in waters outside its exclusive economic zone, between the Korean Peninsula and Japan.

Ukrainian drone strikes on Russia's south killed two people, including an eight-year-old child, the regional governor said on Wednesday after the latest exchange of air attacks between the warring countries.

Russian overnight strikes on a frontline city in southern Ukraine also killed two.

Russian President Vladimir Putin on Wednesday threatened retaliation for Western seizures of its commercial vessels, describing them as "piracy."

Speaking on a visit to a Russian warship that was taking part in a naval exercise in the Pacific, Putin described the Western moves to detain vessels linked to Russia as a breach of international maritime law.

Ukrainian anti-ship missiles, jet-powered aerial drones and sea drones blitzed a major Russian naval base on the Black Sea coast in a "unique" nighttime operation, Ukrainian President Volodymyr Zelensky said Wednesday.

Cutting-edge drones developed by Kyiv since Russia invaded more than four years ago have repeatedly targeted Russian ships in the Black Sea, including warships and oil tankers. Both countries have Black Sea shorelines.

President Donald Trump secretly flew out of last month's NATO summit in Ankara, Turkey, on an alternate military aircraft while the White House made it appear that the Republican president was flying on Air Force One, according to a report published by The Washington Post on Monday.

The Post said the operation was prompted by an Iranian assassination threat against Trump. The ruse was carried out as journalists and some White House staff members were led to believe they were on the same plane as the president as he began his journey back to Washington from the annual gathering of NATO country leaders.

The meeting in the Oval Office between U.S. President Donald Trump and Ukrainian President Volodymyr Zelensky was a diplomatic car crash.

"Your country is in big trouble. You're not winning," Trump said, dressing down Zelensky in front of the world's media. "You don't have the cards."

Ukrainian President Volodymyr Zelensky said Tuesday that Russia fired North Korean missiles in an overnight attack that killed six and wounded 19 in the southeastern city of Zaporizhzhia.

"The city was struck with North Korean ballistic missiles, Zircons, and guided aerial bombs," he said, referring to Russia's hypersonic cruise missile system, Zircon.