Confidence among German business leaders dipped slightly in September but remained strong, a closely-watched survey said Monday, as Europe's export powerhouse nervously eyes an escalating trade war between the United States and China.

The Munich-based Ifo institute's monthly barometer slipped to 103.7 points from 103.9 the previous month, when the index hit its highest level since February.

The reading beat expectations, with analysts surveyed by Factset predicting a steeper drop in morale.

"Despite growing uncertainty, the German economy remains robust," Ifo chief Clemens Fuest said in a statement.

Companies' assessments of both their present economic situation and future expectations fell back somewhat but "remain at a high level", he added.