European Commission chief Ursula von der Leyen Sunday called for progress on a stalled reform of EU asylum rules after the deaths of more than 40 migrants off Italy.

Von der Leyen tweeted that the deaths earlier Sunday, when an overloaded boat carrying around 120 migrants sank, was a "tragedy" that left her "deeply saddened".

"We must redouble our efforts on the (EU) Pact on Migration and Asylum and on the Action Plan on the Central Mediterranean," she said.