Catalans ask Rajoy to agree to an independence referendum

Catalan officials are addressing a letter to Spain's Prime Minister Mariano Rajoy calling for negotiations to agree on a referendum on the northeastern region's independence.

Spanish officials have rejected the unilateral vote planned for Oct. 1. Rajoy has said that a constitutional reform through a strong majority in the national parliament is the only avenue for a legal referendum.

Separatist politicians launched the Yes campaign on Thursday as they press ahead with the vote despite a ban by the country's courts and a criminal investigation into three out of four Catalan mayors actively supporting it.

In the letter, President Carles Puigdemont and Barcelona mayor Ada Colau also say that Spain has launched "an offensive of repression without precedent."

The letter says a copy is being sent to King Felipe VI.