US official say, President Barack Obama is to send 250 additional military personnel to Syria to support local militias in the fight against so-called Islamic state.

The goal, they say, is to encourage more Sunni Arabs to join Kurdish fighters in North-Eastern Syria.

The new deployment will bring to 300 the number of US forces in non-combat roles in Syria. President Obama however says military efforts alone cannot solve Syria's "heart-breaking situation of enormous complexity".