CARACAS, April 29, 2024 (BSS/AFP) - Three Venezuelan activists have been arrested after participating in a campaign rally with opposition leader Maria Corina Machado, her party said Sunday, adding to growing concern over a crackdown on dissent by President Nicolas Maduro's government ahead of the July 28 election.

Ambar Marquez and Victor Castillo, members of Machado's campaign team in the state of Portuguesa, were arrested on Sunday, a day after opposition activist Oscar Castaneda was also detained -- without comment from authorities.

All three had spoken at a rally led by Machado in Portuguesa on Saturday, and add to a growing list of opposition activists detained this year.

Castaneda and Castillo are activists with Machado's Vente Venezuela party, while Marquez was with the aligned Primero Justicia (PJ) party.

"The regime has once again shown its oppressive and violent nature by kidnapping 3 activists from Portuguesa state," PJ said in a post on X, referring to Maduro's government.

"That makes three members arrested in the last 24 hours," wrote Vente Venezuela, on X.

Machado won an opposition primary last year but has been banned from standing in the general election by courts loyal to Maduro, who is seeking a third six-year term.

Another candidate -- the little-known diplomat Edmundo Gonzalez Urrutia -- has been nominated in Machado's place, but she has continued to campaign as the opposition's popular figurehead.

Machado has repeatedly denounced an alleged crackdown on opponents of Maduro, despite an agreement he made with opposition leaders last year to hold free and fair elections.

That agreement saw an easing of US sanctions on Venezuela, but Washington has since announced it will reimpose them, citing the Maduro government's continued repression of opponents.

Prior to the three arrests over the weekend, seven other opposition activists have been detained since January on conspiracy charges, while six others have taken refuge in the Argentine ambassador's residence.