Nearly nine in 10 Spaniards blame Morocco for the mass migrant crossings into Ceuta in late July, while a majority rate Prime Minister Pedro Sanchez's handling of the crisis as "bad" or "very bad", according to an opinion poll released on Monday that also showed a drop in support for Sanchez's party.

The 40dB poll of 2 000 people for El Pais newspaper and radio station SER also recorded an increase in voting intentions for the conservatives and the anti-immigration, far-right Vox party, in line with several other polls conducted after the deadly border surge into Spain's North African enclave. 

For 89% of respondents, Morocco bore the most responsibility for the crisis, followed by human-trafficking groups (75%), the spread of disinformation on social media (74%), the migrants who decided to cross (73%) and the Spanish government (72%), the 40dB poll found.

Only 14.2% rated Sanchez's handling of the crisis positively, with two-thirds of those surveyed saying his response was too slow.

The combined voting intentions for the conservative People's Party and Vox hit 50.2%, leading their potential right-wing alliance to breach the 50% mark for the first time in an opinion poll during this legislature. The centre-left bloc fell to 36.1%.

The PP rose to 32.4%, from 32% in the previous 40dB poll in July, and Vox to 17.8% from 17.2%, while Sanchez's Socialist Party dipped to 27.6% from 28%.

About 27% of respondents named Vox as the most capable party on the issue of immigration, ahead of the Socialists at 18.4% and the PP at 13.9%.

Seven out of 10 chose tighter border controls over protecting vulnerable migrants and 82% backed increasing fences and surveillance at Spain's borders.