Police in Spain have arrested over 50 people across the country, including senior members of the ruling party, in the biggest anti-corruption sweep in the country's history.

Monday's mass raids targeted 51 senior politicians alleged to be part of a huge corruption network, those arrested will face charges of money laundering, embezzlement and influence peddling.

The probe was centred mainly in town halls and regional governments in Madrid and Leon in the centre of the country and Murcia and Valencia in the east.

Francisco Granados, a former secretary-general of the governing Popular Party, was the most prominent figure to be detained.

Granados resigned in February after daily newspaper El Mundo reported that he has almost two million dollars in a Swiss bank account.

Miguel-Anxo Murado, a Spanish journalist, told Al Jazeera from Madrid that members of both the People's Party and the opposition Socialists were among those detained, besides two Madrid mayors.

Those arrested were netted in a vast probe targeting "a network of corruption" that involved local government construction contracts worth roughly $315m, the anti-corruption prosecutor's office said in a statement.

"The collusion between local councillors and civil servants, with builders and energy service companies, and the corruption of middle-men and key companies, has helped them to secure contracts worth around 250 million euros in the last two years alone," the statement said.

The probe is the latest in a string of corruption scandals that have hit Spain's political parties, banks, football clubs and even members of the royal family.

The crackdown also resulted in 400 bank accounts being frozen and around 260 companies being investigated.

Source: Al Jazeera and agencies