U.S. President Donald Trump asked Prime Minister Sanae Takaichi avoid further escalation in a dispute with China during a call this week, sources with knowledge of the matter said, as he aims to keep a fragile trade war truce with Beijing.

Takaichi touched off the biggest diplomatic dispute with Beijing in years with comments in parliament this month that a hypothetical Chinese attack on Taiwan could trigger Japanese military action, inciting fury in Beijing.

In Tuesday’s call with Takaichi, Trump said he didn’t want to see any further escalation, said the two Japanese government sources, who requested anonymity due to the sensitivity of the matter.