The Istanbul Stock Exchange (IMKB)s benchmark National 100 index fell by 7.5 percent in the morning session, with the market spooked by concerns of political instability caused by a senior prosecutor applying on Friday to the courts to have the ruling Justice and Development Party closed on charges of trying to undermine the secular regime.
The Turkish lira fell sharply against the euro, at one point losing 4.8 percent to trade at 2.01 against the European currency. The lira was trading at around 1.27 against the US dollar.
Since the beginning of the year, the IMKBs National 100 index has shed 29 percent in value.
The single biggest loser in Monday mornings session was Turkeys number one mobile phone service supplier, Turkcell, which dropped 10 percent.