* Engineers visit Tabqa Dam, aim to open spillways
* Dam is a strategic target ahead of Raqqa offensive
* Observatory: IS sends 900 fighters to frontlines near
* YPG head: 16,000-17,000 Arab and Kurdish fighters to take
* Graphic: tmsnrt.rs/2l02TCA
By Rodi Said
TABQA DAM, Syria, March 28 Syrian engineers
worked on Tuesday to open spillways and ease pressure on a major
dam across the Euphrates River, amid a pause in a U.S.-backed
assault to capture it from Islamic State, a Reuters witness
The Tabqa dam is a key strategic target in the military
campaign to isolate and capture the Syrian city of Raqqa,
Islamic State's biggest urban stronghold.
The engineers arrived from the dam's northern entrance which
the U.S.-backed Syrian Democratic Forces (SDF) alliance captured
last week. The dam's southern reaches remain in the hands of the
Coalition aircraft could be heard overhead as SDF fighters
manned positions on the dam. Coalition forces in armoured
vehicles were also seen in the area.
Work on the dam was being carried out after the Syrian
government on Sunday said it had been damaged by U.S. air
strikes and could collapse, with the risk of catastrophic
Islamic State said the dam's operating systems were not
working properly and it was vulnerable to collapse. The U.S.-led
coalition later said it saw no imminent danger to the dam,
unless the militants planned to blow it up.
No fighting could be seen or heard at the dam on Tuesday,
according to the Reuters photographer who was at the site for
about 90 minutes.
The UK-based Syrian Observatory for Human Rights on Tuesday
cited sources saying Islamic State had sent 900 fighters from
Raqqa to confront the SDF as it advances on the city on several
fronts. It was not clear where they had been sent to.
The head of the Kurdish YPG militia, fighting in the Raqqa
campaign as part of the SDF alliance, has said the final assault
on the city will begin in early April.
U.S.-backed forces are also battling Islamic State for
control of the Iraqi city of Mosul. Defeats in both would deal a
double blow to Islamic State in the cities from where it
declared its "caliphate" across Syria and Iraq in 2014.
The SDF seized Tabqa air base on Sunday, the first such
facility to fall under the control of Syrian Kurdish militias
and their allies that now control swathes of northern Syria
after six years of multi-sided civil war.
In comments to the London-based Arab newspaper al-Hayat
published on Tuesday, the head of the Kurdish YPG militia said
16,000-17,00 Arab and Kurdish fighters would take part in the
assault on Raqqa.
YPG commander Sipan Hemo also said U.S. Apache attack
helicopters "will participate in providing air support to our
Hemo told Reuters earlier this month that the operation to
storm Raqqa would start in early April and last no more than a
number of weeks. Echoing that assessment, he told al-Hayat "we
will liberate Raqqa in weeks or one month, not more".
Turkey is fiercely opposed to the YPG's role in the Raqqa
offensive, and has been lobbying Washington to abandon the Kurds
and instead work with Ankara and its Syrian rebel allies to take
the city. Turkey sees the YPG as an extension of a Kurdish
militant group that is fighting an insurgency in Turkey.
Washington says a final decision on when and how Raqqa will
be taken has yet to made.
(Writing by Tom Perry in Beirut; editing by Richard Lough)