The Turkish lira was flat on Monday despite another jump in oil prices, and three traders said state banks were again selling dollars to support the currency through market turbulence after the US killing of a top Iranian commander.

The lira was at 5.9735 against the dollar, little changed from Friday's close at 5.9740.

It weakened 11% last year, in part due to Turkey's military incursion in Syria and the threat of US sanctions, bringing losses over the last two years to 36%.

"The state (banks) are in the market on the forex supply side today too, as they were on Friday," one trader said. "It is difficult to say how many dollars are being sold but it's clear they will not allow an excessive loss in the lira's value."

Since March of last year, traders have pointed to occasional state bank interventions to stabilize the lira.

The main BIST 100 share index, which fell 1.94% on Friday, was down 1.4% on Monday.

Investors are also weighing up the outlook for Turkish monetary policy after data on Friday showed annual inflation rose slightly more than expected to 11.84% in December, narrowing the window for more rate cuts in 2020.

The US killing last week of Iranian commander Qassem Soleimani fuelled geopolitical tensions and brought more selling pressure on both the lira and on oil, sending crude prices up another 2% on Monday and hurting emerging-market currencies.