Argentina’s government is set to ramp up pressure on Venezuela to grant safe passage to six opposition aides who had sought refuge in its embassy in Caracas, official sources said, adding they were at physical risk if they didn’t leave the country.

Two senior Argentine officials told Reuters last week that the administration of President Nicolas Maduro, who has looked to head off political rivals ahead of July presidential elections, had reneged on promises to allow the six to safely leave the country.

In March, aides to Venezuelan opposition leader María Corina Machado requested asylum at the Argentine embassy in Caracas, after a local prosecutor issued arrest warrants against them for conspiracy. Machado, who has denied any allegations of misconduct by her team, was blocked from being a candidate in the upcoming election despite being the front-runner in polls.