European markets fell further into the red on Friday afternoon, on the back of weak trade in the U.S., as investors overseas digested the hawkish rhetoric from Federal Reserve officials.

This week, several Fed officials have commented on when might be the best time for the central bank to raise interest rates, especially as the Fed released the minutes from its July meeting on Wednesday. Prior to that release, New York and Atlanta Fed presidents William Dudley and Dennis Lockhart said a September rate hike may be on the table.

Meanwhile, on Thursday, San Francisco Fed President John Williams also signaled support for a rate hike in the near future, saying that waiting too long could be costly for the economy.

Oil prices were another key market mover on Friday, with crude futures coming under pressure in afternoon trade as investors considered the odds of leading producers actually capping their oil outputs in the future. Brent hovered at $50.52, while U.S. crude was at $48.15 a barrel, at Europe’s close.

Meanwhile on the currency front, sterling fell 1 percent against the dollar during trade, after media reports emerged that British Prime Minister, Theresa May wanted to trigger Article 50 by next spring. The pound pared some losses in later trade, standing at $1.3064 at Europe’s close.