BEIRUT – The U.N.-Arab League envoy for Syria warned Tuesday that the country could become another Somalia – where al-Qaida-linked militants and warlords battled for decades after the ouster of a dictator – if the civil war is not ended soon.

Battles between regime forces and Syrian rebels left more than 140 people dead across Syria on Tuesday, while the brother of Syria's parliament speaker was gunned down in Damascus – the latest victim of a wave of assassinations targeting high-ranking supporters of President Bashar Assad's regime.

The violence aroused new concern about the faltering diplomatic efforts to try to end the conflict, with the U.N. political chief warning that the Syria crisis risks "exploding outward" into Lebanon, Turkey and Israel.