By Arshad Mohammed

LONDON (Reuters) - A senior U.S. official on Sunday urged the Syrian opposition to attend a planned international meeting in Rome this week, saying it was a chance for rebels to make their case for more support.

The official, speaking on condition of anonymity, said there was dissension among the opposition about the utility of such meetings and some members have signaled they may not attend.

Nearly 70,000 people have been killed in Syria's civil war in the last 22 months since fighting broke out between rebels trying to oust Syrian President Bashar al-Assad and government forces and allied militias.

There appear to be growing tensions between the fighters on the ground and opposition members outside the country.

"The Syrian opposition leadership is under severe pressure now from its membership, from the Syrian people, to get more support from the international community and in that context there's quite a bit of internal discussion about the value of going to international conferences," the official told reporters travelling with U.S. Secretary of State John Kerry.

"The point that we're trying to make ... is that they have an opportunity in Rome with the meeting that the Italians have offered to host to see the very countries that have been their greatest supporters," the official said.

The Syrian National Coalition said on February 22 that it had turned down invitations to visit Washington and Moscow to protest what it described as international silence over the destruction of the historic city of Aleppo by government missile strikes.

On Saturday, the U.S. State Department issued a statement condemning a Syrian army Scud missile attack that killed dozens of people on Friday in Aleppo, and invited the opposition for talks on finding a negotiated settlement to the conflict.

CHANCE TO MEET KERRY

Invitations from Washington and Moscow had been extended to opposition coalition leader Mouz Alkhatib after he met the Russian and U.S. foreign ministers in Munich earlier this month.

Alkhatib, a cleric from Damascus who has said he is morally obliged to try to seek an exit for Assad without more bloodshed, has been criticized by others in the SNC for acting alone. Continued...