Spanish police have arrested a mother and daughter suspected of shooting dead a politician from the country's ruling party.

Isabel Carrasco, who was killed near her home in Leon, northern Spain, on Monday, was the provincial council leader for the Popular Party (PP)

Officials said one of the women in custody was an engineer who worked for the province and had been sacked from her job and the other person was her mother, the AP news agency reported.

Authorities did not say whether one or both of the women are alleged to have fired shots. The pair were arrested shortly after the killing.

One witness, who asked not to be identified, said he heard five shots as he passed under a footbridge.

He told the newspaper, El Pais, that there were children present near the scene before the shooting.

"Everything indicates that it was personal vengeance," an interior ministry spokesman told the AFP news agency, adding that the weapon involved had not yet been found.

The death of Carraso, 59, a long-time PP local leader, led to politicians halting their campaigns for upcoming European Union elections.

The national government delegate in the Castilla y Leon region, Ramiro Ruiz Medrano, called it "a tragic act without explanation" and said Carrasco was not known to have received any threats.

Spain has seen many political killings over its history, but the interior ministry said Carrasco's did not look politically motivated.

Numerous PP officials were assassinated in the 1990s and early 2000s in killings blamed on the Basque separatist group ETA.

Source: Agencies