Turkey's main opposition party, the Republican People's Party (CHP) organized the demonstration, the latest in a series of protests that resulted in hundreds of detentions and have turned up the pressure on the country's long-time leader,

Turkish authorities said 343 people were arrested during a third day of protests against the detention of Istanbul's mayor.

Hundreds of thousands of Turks protested in Istanbul on Saturday against the jailing of Mayor Ekrem Imamoglu, President Tayyip Erdogan's main rival, sustaining the largest demonstrations Turkey has seen in more than a decade.

Waving flags and chanting slogans, many hundreds of thousands of anti-government demonstrators rallied Saturday in Istanbul in defence of democracy after the arrest of mayor Ekrem Imamoglu which sparked Turkey’s worst street unrest in over a decade.

Turkish authorities say 343 people were arrested during a third day of protests across the country on Friday. The protests began after the arrest of a key opposition figure - Istanbul's Mayor Ekrem Imamoglu - on Wednesday.

Turkey is bracing for more civil unrest, after at least 340 people were arrested overnight Friday during a third day of demonstrations.

More than 1,100 people, including some journalists, were detained in protests against Turkish President Erdogan after the arrest of his rival, Istanbul Mayor Ekrem Imamoglu.

People hold up a poster reading, "Turkey will win", at a rally, to protest against the arrest of Istanbul Mayor Ekrem Imamoglu as part of a corruption investigation, in Istanbul, Turkey,. REUTERS/Louisa Gouliamaki ISTANBUL (Reuters) - Tens of thousands of people gathered in Istanbul on Saturday to protest against the jailing of Mayor Ekrem Imamoglu,