MADRID - Spanish Prime Minister Pedro Sanchez angrily fought back Thursday against allegations that he plagiarised his doctoral thesis, in the same week his health minister resigned over reports of academic irregularities.

“The information appearing in certain media claiming the existence of plagiarism in my doctoral thesis is absolutely FALSE,” Socialist Sanchez tweeted, just two days after Carmen Monton quit the health portfolio under a cloud.

Spanish media said Monton had been awarded grades without attending classes and that her final project contained plagiarised passages - charges she denied.

“I shall take legal action to defend my honour and dignity if what has been published is not rectified,” Sanchez said, after a front-page story by conservative daily ABC saying Sanchez used “cut and paste” to produce his doctoral dissertation.

The article claimed the premier’s paper on innovations in Spanish economic diplomacy, written in 2012 when he was a professor of economics at the private Camilo Jose Cela university near Madrid, included entire paragraphs lifted almost word for word from an article by fellow economists, and from a government presentation. Online conservative paper Ok Diario also accused Sanchez of plagiarism.

In a statement, the Camilo Jose Cela university said it had reviewed the evaluation of Sanchez’s thesis and found it was “carried out in accordance with current regulations and the usual university verification and control protocols”.

The leader of the centre-right Ciudadanos party, Albert Rivera, on Wednesday urged Sanchez in parliament to publish the dissertation, suggesting there were “reasonable doubts” that needed public clarification.

“The thesis has been published in accordance with the rules,” replied an angry Sanchez, in power only since June when his Socialists toppled the conservative Popular Party (PP) which was mired in allegations of corruption, in a no confidence vote.

On Thursday, he took to Facebook to announce in a lengthy post that his thesis would be “completely” available online from Friday, and accuse his opponents of stooping to personal attacks because they “lack political arguments” to oppose his government.

To date, Sanchez’s thesis has only been available at a university library just outside Madrid. It cannot be consulted online and cannot be photocopied, unleashing a rush by journalists on the library for a peek at the document.

Cristina Monge, a political science professor at the University of Zaragoza, said it was common for an author who wishes to publish his thesis in book form - as Sanchez did - to not make it available online.

Sanchez’s Socialist party has only 84 seats in Spain’s 350-seat parliament, the smallest proportion for a government since the country returned to democracy following dictator Francisco Franco’s death in 1975. It relies on support from far-left party Podemos and smaller Catalan and Basque nationalist formations.

This is the latest in a string of cases where Spanish politicians have had their academic credentials questioned.

The new head of the PP, Pablo Casado, faces calls to step down after he admitted to obtaining a master’s degree from King Juan Carlos University without attending classes or turning in a final dissertation.

A bench of the Supreme Court is to decide shortly whether an investigation should continue into whether Casado was party to corrupt acts.

Casado has repeatedly refused to resign and his Party Popular has stood resolutely by him.

Another PP figure, Cristina Cifuentes, was forced to resign as head of the Madrid regional government after doubts were raised about her qualifications from University Rey Juan Carlos - the same university where Monton, Sanchez’s former health minister, obtained her degree.

Monge warned the repeated scandals could fuel voter anger.

“Many parents pay a great deal (for their children’s studies) and this creates a sense of injustice among the middle classes, the voters of Ciudadanos, and the PP,” the analyst said.