A sustained strength above a three-day-old descending trend-line resistance, around the 0.6405-10 region, was seen as a key trigger for bullish traders and behind the latest leg of an upsurge witnessed since the mid-European session amid improving risk sentiment. Meanwhile, technical indicators on 4-hourly/daily charts have been gaining some bullish traction and support prospects for an extension of the ongoing positive momentum. However, slightly overbought conditions on the 1-hourly chart warrant some caution. Hence, any subsequent move up seems more likely to confront a stiff resistance near the 0.6445-50 heavy supply zone, which if cleared decisively might negate any near-term bearish bias and set the stage for a further near-term appreciating move for the pair.