The Turkish lira fell against the United States dollar due to mounting tensions between Turkey and the U.S. in the wake of Ankara's refusal to release American pastor Andrew Brunson who is suspected of being involved with a terrorist group.
Shares of European lenders also dropped, which according to the Reuters news agency was due to concerns about their Turkey exposure.
Speaking in the Black Sea privince of Rize late on Thursday, Mr Erdogan told supporters: "There are various campaigns being carried out".
"Many of these European banks have their own non-performing loans and liquidity issues to deal with themselves".
The report said that the situation is not yet seen as "critical" but Spain's BBVA, Italy's UniCredit and France's BNP Paribas are regarded as particularly exposed.
Investors fear Turkey is teetering on the edge of financial crisis following a dramatic plunge in its currency that has gathered pace this week.
Turkey's lira hit a new record low against the USA dollar in early trade on Friday, as concerns over a widening rift with the United States persisted after a Turkish delegation returned from talks in Washington with no apparent solutions to the crisis.
Investors are now awaiting the release of the US consumer price inflation for July for clues on the interest rate outlook and to gauge if new import tariffs were starting to have an impact.
The dollar index.DXY, which measures the greenback's strength against a group of six major currencies, breached the 96 level, taking it to its highest level since July 2017.
Adding to emerging market currency woes was the Russian rouble, which weakened to 67.12 to the dollar. The dollar, which traders buy in times of financial concern, was up against most other currencies.
He said: "If they have their dollar, we have the people, we have Allah".
In commodities, USA crude oil rose half a percent to $67.16 a barrel, while Brent crude was 0.6 percent stronger at $72.47 per barrel.
The 19-country currency fell 0.7 percent to trade at $1.1450 in morning trading in Europe.
Spot gold rose 0.1 percent to $1,213 per ounce.