Madrid: The Spanish police have arrested 50 people across the country as part of an ongoing operation against an Indian network accused of tax fraud and other crimes in its commercial dealings, sources close to the investigation said Tuesday.

Some 150 houses in different Spanish regions were being searched, while authorities have issued 78 arrest warrants, although so far only 50 people have been detained, the sources said.

The operation is the result of a probe launched in 2012 by the tax fraud national bureau to dismantle an organisation which illegally imported goods into Spain, mainly textiles, medicines and electronic material coming from China and the European Union.

The products, which evaded taxes, were later sold cheap without the value added tax.

The organisation, which includes Indian and Spanish citizens, has also been accused of money laundering, smuggling, violations in the field of industrial and intellectual property and crimes against public health and bribery.

The biggest search was being conducted in an industrial area on the outskirts of Madrid, but others were carried out in different Spanish regions as well as in neighbouring Portugal and in Italy.