Madrid: US Defence Secretary Ashton Carter said Monday that Russia is pursuing a “losing strategy” in Syria and that it must live up to its commitments in Ukraine.

Speaking in Madrid at the start of a five-day trip to Europe, Carter told Spanish military officials that by carrying out bombing in Syria, Russia had only worsened the four-year conflict.

“Russia has escalated the civil war, putting further at risk the very political resolution and preservation of Syria’s structure of future governance it says that it wants,” Carter said.

“It remains my hope that Vladimir Putin will see that tethering Russia to a sinking ship is a losing strategy, and will decide to confront the threat presented by (Daesh) instead of continuing its unilateral air strikes against Al Assad’s opposition.”

Carter’s trip is aimed at acknowledging allies in the 60-plus member US-led coalition that is carrying out daily drone and plane strikes against Daesh terrorists in Iraq and Syria.

It demanded that “any such violation not be repeated”, otherwise Russia “will be responsible for any undesired incident that may occur.”

The tour comes at a fraught time for Carter, who started in the Pentagon’s top job in February and who faces pressure at home over Syria and a simmering scandal involving military officials allegedly cherry-picking intelligence.

Carter on Thursday is attending a NATO ministerial summit that is expected to tackle a number of issues including Russian aggression in eastern Ukraine.

“We will continue to make it clear that if Russia wants to end its international isolation and be considered a responsible global power, it must stop its aggression in eastern Ukraine, end its occupation and attempted annexation of Crimea, and live up to its commitments under the Minsk agreements,” Carter said.

“We will take all necessary steps to deter Russia’s malign and destabilizing influence, coercion, and aggression, including its efforts to undermine strategic stability and challenge the military balance in Europe.”