Mobile operator Telefónica Móviles has appealed to Madrid residents to limit their mobile phone calls to reduce network congestion after this morning's bomb attacks in the Spanish capital.

More than 170 people were reportedly killed after four bombs went off at busy train stations at the beginning of the morning rush hour.

The Spanish elections are due to take place this Sunday, and although no one has claimed responsibility, the BBC reports that the Spanish government blames Basque separatists Eta for the blasts.

A government spokesman condemned the incident as an attack on democracy, and called Eta "a criminal gang of killers".

A spokesman for Telefónica Móviles said that the worst of the network congestion had passed, but asked that people send texts rather than make calls, Bloomberg reports. ®