By Agence France-Presse
ECB boss Mario Draghi sent the euro surging past $1.20 for the first time since the beginning of January 2015 by saying policymakers would decide next month on the bank's plans for its bond-buying scheme.
While not openly saying that it would begin to cut back on the programme, his comments -- and his lack of concern about the strong euro -- were taken as a nod that the tapering would begin soon.
The remarks came as figures showed the eurozone economy continued to improve in the second quarter.
"Growth at these levels does not warrant the continuation of the ECB's bond-buying programme. So it must end. The ECB knows it and the market knows it. That's what is driving the euro higher and it's what is complicating the decision for the ECB on the when and how," said Greg McKenna, chief market strategist at AxiTrader.
The dollar was also coming under pressure from concerns about the impact of Hurricane Irma, which is about to strike Florida this weekend, while the chances of Donald Trump pushing through his market-friendly economic agenda are slimming.
"Investors have renewed their interest on the US political overhang as the political landscape continues to weigh heavily on the dollar. Specifically, the long and winding and no less bumpy road to tax reform looks more of a pipe dream now than ever," said Stephen Innes, head of Asia-Pacific trading at OANDA.
The greenback is at its lowest levels since November and could fall below the 108 yen, analysts warned.
North Korea tensions, which fuelled a global sell-off after Pyongyang tested what it said was a hydrogen bomb Sunday, were eased a little by Trump's remarks that a US military strike was "not inevitable".
However, with world powers struggling to agree on a way to address the crisis markets remain on edge, with many observers fearing the North will conduct another missile test on Saturday.
On equity markets Tokyo ended the morning 0.4 percent lower with exporters hit by the stronger yen while figures showed the Japanese economy continued to expand in the second quarter but at a slower pace that first thought.
Sydney was down 0.3 percent and Shanghai gave up 0.1 percent but Hong Kong edged up 0.3 percent and Singapore was 0.2 percent higher. Wellington and Taipei were also slightly up.
Key figures around 0230 GMT
Tokyo - Nikkei 225: DOWN 0.4 percent at 19,322.74 (break)
Seoul - Kospi: DOWN 0.1 percent at 2,343.59
Hong Kong - Hang Seng: UP 0.3 percent at 27,616.63
Shanghai - Composite: DOWN 0.1 percent at 3,363.88
Euro/dollar: UP at $1.2036 from $1.2028 at 2040 GMT
Pound/dollar: UP at $1.3107 from $1.3103
Dollar/yen: DOWN at 108.31 yen from 108.43 yen
Oil - West Texas Intermediate: UP three cents at $49.12 per barrel
Oil - Brent North Sea: UP six cents at $54.55 per barrel
New York - DOW: DOWN 0.1 percent at 21,784.78 (close)
London - FTSE 100: UP 0.6 percent at 7,396.98 (close)