New York, The US dollar index rose slightly as risk appetite prompted weakening of euro, Japanese yen, Australian dollar and Canadian dollar.
In late New York trading on Tuesday, the euro was down to $1.1129 from $1.1138 in the previous session, and the British pound was up to $1.3028 from $1.2998 in the previous session, Xinhua reported.
The Australian dollar declined to $0.6904 from $0.6906.
The US dollar bought 109.98 Japanese yen, higher than 109.91 Japanese yen of the previous session. The US dollar decreased to 0.9673 Swiss franc from 0.9706 Swiss franc, but it increased to 1.3058 Canadian dollars from 1.3047 Canadian dollars.
Though improving trade ties between the US and China should bode poorly for greenback prospects, foreign exchange flows were rather quiet in anticipation of the phase-one trade deal to be signed to give global markets much-desired good news, according to US foreign exchange and international payment services company Tempus Inc.
Swiss franc appreciated substantially against the US dollar on Tuesday after the USput Swiss franc on its watch list regarding currency manipulation on Monday.
The Swiss franc is mounting a bit of a comeback after losing ground since the start of the year based on the chance that the Swiss National Bank will have to get rid of negative interest rates, said Tempus Inc in a note.
The dollar index, which measures the greenback against six major peers, picked up 0.02 per cent to 97.3690.