Anglela Merkel's government has been plunged into political controversy after the sacking of Harold Range, the attorney-general.

Mr Range accused the German government of meddling in a treason probe shortly before he was dismissed.

Senior MPs from her own Christian Democrats have broken ranks to criticise the decision, linked to a treason investigation into a pair of journalists.

But Mrs Merkel has publicly backed the attorny-general's dismissal.

Heiko Maas, the justice minister, dramatically fired Mr Range on Tuesday night after the attorney-general accused the government of “intolerable interference in the independence of the judiciary”.

Mr Range’s outburst came after Mr Maas had intervened to shut down his investigation of two journalists on possible treason charges.

Mr Range ordered the investigation against Markus Beckedahl and Andre Meister of the news website Netzpolitik.org after they published classified information that had been leaked to them.

They reported that Germany’s domestic security service was intending to extend its monitoring of onlne communication.

There has been growing concern over recent leaks in Germany, but Mr Range’s decision to go after the journalists for a crime as serious as treason provoked a public outcry

The publication of state secrets is considered treasonous under German law.

But Mr Range’s attempt investigate the journalists under the law was widely seen as an assault on the principle of free speech.

The only previous attempt to prosecute journalists under the law, during the Spiegel Affair of 1962, failed and cost the then defence minister his job.

That is seen as a landmark victory for free speech in modern Germany.

On this occasion, Mr Maas swiftly intervened and ordered the investigation suspended while the case against the journalists was externally assessed.

The Chancellor doubted that the journalists were guilty of treason, and “expressly supported” the suspension of the invesigation, Christiane Wirtz, her deputy spokesman said.

Thomas de Maiziere, the Interior Minister, also cast doubt on the case against the journalists.

Now, though, senior MPs are demanding answers over the case.

“If Mr Maas suddenly dismisses the attorney-general, that’s strange behavior,” Hans-Peter Uhl of the Christian Democrats’ Bavarian sister party, the CSU, told Handelsblatt newspaper.

“I think it’s excessive, and therefore also false.”

Mr Uhl said he believed the justice ministry must have been aware of the treason investigation, which he said Mr Range had been working on for three months.

Wolfgang Bosbach of the Christian Democrats, also demanded clarity over when Mr Maas first knew of the investigation.

Mr Bosbach said it was understandable for the justice minister to fire Mr Range after his public outburst.

“But it remains unclear why he didn’t wait for the outcome of the report,” he said.

But Thomas Strobl, deputy chairman of the Christian Democrats, said Mr Range’s dismissal was inevitable after he had publicly criticised the government.

“The feud between the attorney-general and the ministry of justice couldn’t continue in any case,” he told Welt newspaper.