Egypt's foreign ministry has summoned the British ambassador over comments he made on a court's decision to hand down prison sentences for three Al Jazeera journalists, state television has reported.

The Cairo court sentenced Egyptian Baher Mohamed and Canadian Mohamed Fahmy to three years in prison while Australian Peter Greste was sentenced in absentia.

Speaking in Arabic after the verdict, John Casson said he was concerned the sentencings could "undermine confidence in the basis of Egypt's stability, both in Egypt and abroad".

The comments were posted on the British embassy's Facebook page.

Ahmed Abu Zeid, a spokesperson for the ministry, tweeted on Sunday that the ministry rejected any foreign criticism of the legal system, calling them an "unacceptable intrusion" in the country's judiciary.

#Egypt rejects any foreign criticism of judicial verdicts, considers it an unacceptable intrusion in rulings of Egyptian judiciary #AJTrial — Egypt MFA Spokesman (@MfaEgypt) August 30, 2015

He also said the latest verdicts were "unrelated to freedom of the press but rather to specific, documented legal violations".

Thousands of Egyptian & foreign journalists are currently working in Egypt with complete freedom #AJTrial — Egypt MFA Spokesman (@MfaEgypt) August 30, 2015

Several other foreign diplomats at the trial also condemned the verdict, but Casson may have been the only one to speak in Arabic to domestic television stations, the AP news agency reported.

Casson's comments appeared on Twitter as well.

Meanwhile on Saturday, Britain's minister for the Middle East and North Africa , Tobias Ellwood, said he was "deeply concerned by the sentences".

Watch: Dark day for press freedom?

Ellwood said that the "sentences will undermine confidence in Egypt’s progress towards strong long-term stability based on implementing the rights granted by the Egyptian constitution".

The journalists and Al Jazeera vigorously denied the accusations during the course of the trial.

Speaking from Sydney on Saturday, Greste said he was "shocked" by the court's decision and that the verdicts were "unjust" and "unethical".

"We will do everything we can to fight the verdict to clear our names. We are not terrorists. We did not collude with any organisation. We did not broadcast any false news," Greste said.

Greste called on Egyptian President Abdel Fattah el-Sisi to pardon the journalists and said the president "now has an opportunity to undo that injustice".

Trying to do their jobs

Saturday's verdicts prompted international outrage.

Opinion: #FreeAJStaff: Travesty of justice continues

A spokesman for the UN high commissioner for human rights, Prince Zeid bin Raad, said: "We are very disturbed by these three sentences and the extra pressure it creates on journalists in Egypt who are just trying to do their jobs."

The European Union said the verdict was "a setback for freedom of expression in Egypt".

Al Jazeera has said it plans to file an appeal before the Court of Cassation.

In January, an appeals court ordered a retrial, saying the initial verdict lacked evidence against the three journalists.

Lynne Yelich, the Canadian minister of state for foreign and consular affairs, issued a statement after the verdict calling on Egyptian authorities to release Fahmy.

"Canada is disappointed with Mohamed Fahmy's conviction today. ‎This decision severely undermines confidence in the rule of law in Egypt," Yelich said.

"The government of Canada continues to call on the Egyptian government to use all tools at its disposal to resolve Mr Fahmy's case and allow his immediate return to Canada."