Ukrainian drone strikes damaged energy networks in Russia-occupied parts of southern Ukraine, leaving hundreds of thousands of people without power on Sunday, according to Kremlin-installed authorities there.

Meanwhile, Moscow has kept up its hammering of Ukraine's energy grid in overnight attacks that killed at least two people, according to Ukrainian officials.

A U.S.-based activist agency said Sunday it has verified at least 3,919 deaths during a wave of protests that swept Iran and led to a bloody crackdown, and fears the number could be significantly higher.

The Human Rights Activists News Agency posted the revised figure, up from the previous toll of 3,308. The death toll exceeds that of any other round of protest or unrest in Iran in decades, and recalls the chaos surrounding the 1979 revolution.

Wildfires raging across central and southern Chile have left at least 18 people dead, scorched thousands of acres of forest and destroyed hundreds of homes, authorities said, as the South American country swelters under a heat wave.

Chilean President Gabriel Boric declared Sunday a state of catastrophe in the country's central Biobio region and the neighboring Ñuble region, around 500 kilometers (300 miles) south of Santiago, the capital.

Spanish police said Monday that at least 39 people died in the high-speed train collision Sunday in southern Spain and rescue efforts were continuing.

The collision occurred when the tail end of a train traveling between Malaga and Madrid with some 300 passengers went off the rails near Cordoba at 7:45 p.m. It slammed into an incoming train from Madrid to Huelva, another southern Spanish city, according to rail operator Adif.

Iranian authorities have said they are considering "gradually" restoring internet access after imposing a sweeping communications shutdown across the country more than a week ago, local media reported.

Iran's supreme leader Ayatollah Ali Khamenei on Saturday accused U.S. President Donald Trump of being responsible for "casualties" during a protest wave in the country that rights groups said was met with a deadly crackdown.

The son of Iran's late shah said Friday he was confident that mass protests would topple the Islamic republic and urged international action, as U.S. President Donald Trump holds off on intervening in the unrest.

Tens of thousands of Cubans crowded Friday into an open-air plaza known as the "Anti-Imperialist Tribune" across from the U.S. Embassy in Havana to decry the killing of 32 Cuban officers in Venezuela and demand that the U.S. government release former president Nicolás Maduro.

The crowd clutched Cuban and Venezuelan flags as part of a demonstration organized by the government as tensions between Cuba and the U.S. remain heightened after the U.S. struck Caracas on Jan. 3 and arrested Maduro.

Russia has not spared a single Ukrainian power plant from attack since its all-out invasion, Ukraine's new energy minister said Friday, as a recent escalation of aerial bombardments left hundreds of thousands of people without heat or light for days amid the coldest winter for years.

Denys Shmyhal said Russia conducted 612 attacks on Ukraine's energy infrastructure objects over last year. That barrage has intensified in recent months as nighttime temperatures plunge to minus 18 degrees C (minus 0.4 F).

Russian President Vladimir Putin on Friday held phone calls with Israeli Prime Minister Benjamin Netanyahu and Iranian President Masoud Pezeshkian, the Kremlin said, offering mediation amid large-scale protests in Iran.

"Vladimir Putin held a telephone conversation with Israeli Prime Minister Benjamin Netanyahu," the Kremlin announced in a statement, asserting "Russia's readiness to continue its mediation efforts."