
Qatar's Emir Sheikh Tamim bin Hamad al-Thani has warned that the US-led  fight against Islamic State militancy will not succeed as long as Syrian  President Bashar Assad remains in power.
US and Arab forces have  bombed Islamic State targets in northern and eastern Syria this week,  following US strikes on the al-Qaida splinter group in Iraq since early  August.
"We have to counter terrorism, yes. But I believe that  the main cause of all this is the regime in Syria, and this regime  should be punished," Sheikh Tamim said in an interview with CNN  broadcast on Thursday.
"...If we think that we're going to get  through the terrorist movements and leave those regimes doing what they  -- this regime especially, doing what he is doing -- then terrorist  movements will come back again," he said, according to a transcript of  the interview.
Islamic State fighters have exploited the chaos of  Syria's three-year-old civil war, which pits Assad and his allies  against mainly Sunni Muslim rebels and Islamist militants, to carve out  territory in the country's eastern provinces.
Qatar, which has  sent cash and arms to rebels fighting Assad, also supported the US  strikes against Islamic State, contributing one plane on the first night  of attacks on Tuesday.
Other US allies Jordan, Bahrain, the  United Arab Emirates and Saudi Arabia have joined in the strikes. All  are ruled by Sunni Muslims and are opponents of Assad, a member of a  Shi'ite-derived sect, and his main regional ally, Shi'ite Iran.
The  air raids follow growing alarm in Western and Arab capitals after  Islamic State, a Sunni militant group, swept through a swath of Iraq in  June, proclaimed a "caliphate" ruling over all Muslims, slaughtered  prisoners and ordered Shi'ites and non-Muslims to convert or die.