Oil prices gained on Tuesday as the market steadied after several days of declines, with investors awaiting developments on potential US-Iran talks at the United Nations General Assembly this week. The Brent crude futures November contract gained 22 cents, or 0.22%, to $100.57 a barrel at 0021 GMT. The WTI October contract, which expires on Tuesday, crept up 2 cents, or 0.02%, to $95.8 a b