Turkish army tanks gather close to the Syrian border on January 21, 2018 at Hassa, in Hatay province | Bulent Kilic/AFP via Getty Images Germany faces calls to end arms exports to Turkey Turkey’s use of German Leopard tanks in offensive against Kurds risks worsening rocky Turkish-German relations.

A number of German politicians are calling on the government to cease arms exports to Turkey, following reports that Turkish forces used German-made tanks in an offensive against Kurdish groups, the BBC reported on Wednesday.

Turkish forces began an offensive Saturday in the Afrin region of northern Syria to drive out the People's Protection Units (YPG) militia, which controls the region around Afrin. The operation has killed at least 260 Syrian Kurdish and Islamic State fighters and displaced around 5,000 civilians.

German media reported that the offensive was carried out partly by German Leopard tanks, worsening the already controversial assault by Turkey that drew calls for restraint from world leaders, including U.S. President Donald Trump and French President Emmanuel Macron.

Ankara has requested for months that German arms manufacturers upgrade its Leopard 2 tanks — previously thought to have been used exclusively in the fight against the Islamic State in Syria — with better armor and defense systems. Recent reports suggest that Berlin was considering approving the request, drawing criticism from German politicians on both the right and the left.

Norbert Röttgen, chairman of the parliamentary foreign affairs committee and a member of Angela Merkel's conservative party, told BBC Radio 4 that it was "completely obvious" Germany should refuse to upgrade the tanks.

The tank controversy comes in the wake of a friendly meeting earlier this month between Foreign Ministers Sigmar Gabriel and Mevlüt Çavuşoğlu that some hoped would improve relations between the two countries, which are at their lowest point in decades. Berlin has led criticism of Turkish President Recep Tayyip Erdoğan’s turn toward authoritarianism, which has included the arrest of a number of German citizens on what Berlin considers bogus grounds.

Gabriel said Monday he had called his Turkish counterpart after the offensive to express his concern.

Germany exported weapons and other military equipment worth €3.79 billion to third countries in 2017, Spiegel reported. The topic is likely to play a role in ongoing coalition talks between Angela Merkel's conservatives and the Social Democratic Party, which has called for a more restrictive policy on arms exports.