CARACAS, Venezuela -- The Trump administration slapped economic sanctions on Venezuela's president Monday. Treasury secretary Steven Mnuchin said Nicolas Maduro has become a dictator -- after holding an election Sunday designed to give himself absolute power.

At least 140 people have been killed in protests in Venezuela's capital, and the clashes between protesters and police are looking more like all-out war.

Several officers were hurt in an explosion, and at least 10 demonstrators were killed as they tried to disrupt the vote this weekend.

But Diana Osuna, 22, still decided to march wearing only an equestrian helmet.

Diana Osuna CBS News

"You can see the people -- that's it is really sad, but they are still in the streets, still screaming for what they want -- their freedom and liberty," Osuna told CBS News.

Neither has been much in evidence this election. There were no opposition parties listed on the ballot. Instead, President Nicolas Maduro wants a new assembly to rewrite the constitution.

Venezuelans weren't asked to vote on the plan -- only on who will be a part of it.

Maduro's supporters said it was the only way to restore law and order -- especially "paz" (or peace) as one man said.

The crisis here is as much an economic one. The country went into a financial nosedive when oil prices fell, leading to skyrocketing inflation and shortages of food and medicine.

Freddy Guevara CBS News

Lawmaker Freddy Guevara vows the opposition will go on.

"We have to go forward with the pressure on the streets, we have to go forward with the international pressure," Guevara explained. "And we have go and go like a river that goes to the ocean, until the Venezuelan people get free."

Protesters vow to keep taking to the streets while more turmoil is likely ahead as the newly-elected assembly could meet Wednesday to start drafting the new constitution.