The dollar rose on Friday, posting its biggest weekly percentage increase in a month, as risk appetite declined and investors sought the currency's safety following a steep drop in oil prices that suggested global growth is slowing. The safe-haven yen and Swiss franc also advanced.
The drop in oil prices fuelled a risk-off wave across the board. US crude futures were last down nearly 8 percent on the day.
"Risk aversion has been the main driver all week, with oil prices driving market sentiment," said Shaun Osborne, chief FX strategist at Scotiabank in Toronto.
"The dollar is better overall for the week because of the risk-off stance, despite a fairly significant pricing out of 2019 rate hike expectations," he added.
In afternoon trading, the dollar index was up 0.3 percent at 96.959. It has gained in five of the last six sessions.
The dollar's near-term outlook, however, has dimmed a little bit as some of the recent US economic numbers have come in weaker than expected and several Federal Reserve officials have struck a cautious tone on the economy. All told, investors increasingly believe the Fed may be nearing the end of its tightening cycle.
That said, Jane Foley, senior FX strategist at Rabobank in London, believes the dollar will still find decent support as investors are likely to remain cautious on emerging market assets.
"The huge liquidity associated with the greenback, the fact that there is no real default risk on US Treasuries, and the credibility of the US legal system are enough to endow the US dollar with sufficient safe-haven appeal for many investors," Foley added.
The euro, on the other, fell to a one-week low on signs economic growth could be slowing across the euro zone, with worries about Brexit and Italy's budget negotiations also weighing on the single currency.
Business growth in the euro zone slowed much more quickly than expected this month, a Purchasing Managers Index survey showed. After German private-sector growth slowed to its lowest level in nearly four years, the euro dropped into negative territory and was last down 0.7 percent at $1.1329.
In other currency trading, the yen rose broadly on fears about the implications of lower oil prices on global growth.
The dollar slipped 0.1 percent against the yen to 112.86 yen, while the euro tumbled 0.7 percent to 127.86 yen.
The Australian dollar, often considered a gauge for global risk appetite, weakened 0.4 percent to U$0.7225.
Analysts expect the Aussie to remain subdued ahead of a meeting between US and Chinese leaders at a G20 meeting in Argentina at the end of the month, with markets watching for any sign of whether they may agree to de-escalate their trade war.