Mumbai, Aug. 22 -- The Indian rupee is likely to stay cautious as greenback gains momentum ahead of Federal Reserve (Fed) Chair Jerome Powell's speech later today at Jackson Hole for further clarity on Fed's interest rate stance. Yesterday, rupee pared initial gains and settled for the day lower by 18 paise at 87.25 against US dollar. Rupee opened on a positive note with the rise in risk appetite in the global markets amid easing tensions over trade tariffs and hopes of truce between Russia and Ukraine. However, the strength of the American currency in the overseas market and rising crude oil prices dented investor sentiments and restricted the upmove in the local unit. Indian shares extended gains for a sixth day running on Thursday as i...