Beirut/United Nations (Reuters) - The United Nations on Friday confirmed that veteran Algerian diplomat Lakhdar Brahimi would become the new international mediator on Syria, as the 17-month-old conflict slid deeper into civil war and refugees fled to Turkey in increasing numbers.

 
President Bashar al-Assad's forces have turned increasingly to air power to hold back lightly armed rebels in the capital Damascus and Aleppo, a northern commercial hub. More than 18,000 people have died and some 170,000 have fled the country as a result of the fighting, according to the U.N.

 
Brahimi, who hesitated for days to accept a job that France's U.N. envoy Gerard Araud called an "impossible mission," will replace former U.N. Secretary-General Kofi Annan, who is stepping down at the end of the month.

"The (U.N.) Secretary-General appreciates Mr. Brahimi's willingness to bring his considerable talents and experience to this crucial task for which he will need, and rightly expects, the strong, clear and unified support of the international community, including the Security Council," U.N. spokesman Eduardo del Buey said.

 
U.N. Secretary-General Ban Ki-moon and Arab League chief Nabil Elaraby back Brahimi's appointment, said del Buey, who added that achieving a diplomatic solution to the Syrian crisis remained a top priority for the United Nations.

 
Diplomats said all Security Council members supported Brahimi.