The crackdown by Venezuela President Nicolas Maduro - now officially branded a dictator by the U.S. - on political opposition intensified Tuesday when intelligence agents detained opposition leaders Leopoldo Lopez and Antonio Ledezma at gunpoint in their homes and took them into custody.

The two politicians have been under house arrest for their involvement in anti-government protests and organizing, according to the BBC. Videos published online by family members of both men show them being led away in the middle of the night by agents from Sebin, the Venezuelan intelligence agency. Lopez’s wife Lilian Tintori said in a tweet: “They’ve just taken Leopoldo from the house. We don’t know where he is.” She published grainy footage from the home’s security cameras showing her handcuffed husband being placed in the back of a car.

Momentos en que @leopoldolopez see llevado por funcionarios del SEBIN. ( Sigue sin conocerse su pradero) pic.twitter.com/BrIURSa7q0 — #SOSVenezuela (@aura_rojas) August 1, 2017

“If something happens to him, Maduro will be held responsible,” Tintori said, according to Bloomberg.

Vanessa Ledezma, the daughter of the former Caracas mayor, posted video of her father being taken away by the Sebin, the Venezuelan intelligence agency, in his pajamas. In the video, a woman can be heard shouting: "They're taking Ledezma, they're taking Ledezma, dictatorship!"

Video apparently show arrest of Caracas, Venezuela Mayor Antonio Ledezma overnight @nbc6 https://t.co/AmFbB5YTsU — Julia Bagg (@JuliaNBC6) August 1, 2017

According to the BBC, both men were key figures in protests that that led to 43 deaths, including anti- and pro-government demonstrators. Though their role in the opposition movement has been diminished by house arrest, video messages by both men are still shared widely on opposition websites. Ledezma published a video on Monday where he called the constituent assembly a "fraud" and denounced the "tyranny" of the Maduro regime.

In a Sunday vote that was boycotted by the opposition, Maduro’s government claimed overwhelming victory, saying their candidates had won all 545 seats in the assembly, which will replace the opposition dominated National Assembly, which was disbanded by the Maduro-aligned Supreme Court in March. At least 10 demonstrators died during the vote as protesters tried to disrupt the vote, erecting barricades around polling stations. The US, UK, European Union, Australia and Argentina have refused to recognize the vote.

According to Bloomberg, Lopez has become a symbol for human-rights groups and foreign governments, who’ve said his detention, including stints in solitary confinement, was clear evidence that Maduro was willing to trample basic rights to safeguard his power. Opposition leaders and family members of both say their whereabouts are unknown.

Maduro is seeking to rewrite the constitution after a referendum on Sunday that the opposition and many foreign governments refused to recognize. Opponents regard the push to overhaul the charter as a power grab by an increasingly autocratic leader.

On Monday, the Treasury's Office of Foreign Assets Control (OFAC) personally sanctioned Maduro, adding him to a list of 13 other senior government officials who have been shut out of the US financial system. There’s speculation that the US could press sanctions against the state-controlled energy industry, something that RBC’s top commodity analyst has speculated that Venezuela, which has the largest oil reserves of any country on Earth, could be the first major oil producer to see an all-out economic collapse. Government officials have said energy-industry sanctions would worsen the country’s economic crisis in a way that would disproportionately harm the country’s most vulnerable citizens.

Maduro's regime has remained defiant, according to Al Jazeera.

"They don't intimidate me. The threats and sanctions of the empire don't intimidate me for a moment," Maduro told a cheering audience. "I don't listen to orders from the empire, not now or ever. Bring on more sanctions," he told US President Donald Trump.

The country’s economy has been declining since shortly after Maduro, the hand-picked successor to deceased socialist icon Hugo Chavez, took office in 2013, as years of economic mismanagement and collapsing oil prices squeezed the government’s access to foreign currency, sparking a vicious cycle of hyperinflation. Presently, the country’s currency, the Venezuelan bolivar, is trading at more than 11,000 to the dollar in Caracas’s black markets, according to dolartoday.com. Meanwhile, the country’s foreign reserves have tumbled below $10 billion, sending yields on its dollar-denominated debt north of 36%, according to Bloomberg.

“The nation’s $3 billion bonds due 2022 plummeted, sending the yield soaring 86 basis points as of 9:43 a.m. in London to close to 40 percent, the highest level on a closing basis since February 2016. Bets on a Venezuelan default are climbing and the implied probability of a missed payment over the next year has risen to 64 percent, according to data compiled by Bloomberg on credit-default swaps.”

The country’s economic outlook looks increasingly dire by the day: by the end of this year, it’s expected that its economy will have shrunk by 32% compared to where it was at the end of 2013, according to the IMF. Of course, as at least one analyst has noted, the US’s attempts to pressure Maduro with sanctions will likely only push his regime further into "unfriendly" orbit, either that of China or Russia. In exchange for a loan from Russian oil giant Rosneft in December, Venezuela's state-owned oil company, Petroleos de Venezuela, put up a 49.9% in Citgo, its US arm, which could leave Russia in control of what Congress has labeled critical infrastructure. Also, as reported previously, China has repeatedly provided loans to Venezuela in the past in exchange for oil, although its eagerness to do so in recent months has waned substantially.