Turkey's central bank yesterday sought to reassure investors over its foreign currency reserves after the sharpest drop in the local lira since a spat with the United States triggered a currency crisis last year.

The lira slid nearly 6 percent on Friday, prompting President Recep Tayyip Erdogan to call for a crackdown on market "manipulations" and Turkish regulators to open a probe into investment banks.

After recovering losses early this week, the lira fell again around 5 percent to 5.59 against the dollar on Thursday morning, prompting Erdogan to blame fluctuations on a Western plot to undermine Turkey.

Lira turmoil is sensitive for Erdogan before Sunday's municipal elections when his ruling AKP party is battling to win major cities after the economy slipped into recession for the first time in a decade.