The US President Barack Obama has spoken in support of press freedom in countries including Egypt, where four Al Jazeera staff have been imprisoned by authorities.

Obama was speaking at the annual White House Correspondents' dinner in Washington DC on Saturday, which coincided with World Press Freedom Day.

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"Our thoughts are with those who are in places like Ukraine and Aghanistan and Syria and Egypt who risk everything and in some cases their lives to report the news," Obama told 2,000 guests at the event.

The dinner is traditionally marked by the US president making self-deprecating remarks and jokes at the expense of political opponents and media personalities.

While Obama did not directly mention the Al Jazeera journalists being held in Egypt, the case has achieved international attention after a social media campaign.

All four journalists appeared before Egyptian judges on Saturday.

Baher Mohamed, Peter Greste and Mohammed Fahmy, from the Doha-based network's English channel, were denied bail and their case was adjourned until May 15.

They face charges of spreading false news and working with the Muslim Brotherhood, an organisation which has been banned in the country.

In a separate hearing, Al Jazeera Arabic's Abdullah El Shamy, was told he would spend another 45 days in detention. He has been in prison for more than 262 days without charge, and has been on hunger strike for more than a 100 days in protest.

Al Jazeera rejects all charges and accusations against its staff.

Source: Al Jazeera