New Delhi, June 29 -- The US dollar was on track for its biggest monthly gain in nearly a year, boosted by safe-haven bets amid the US-Iran war in the Middle East and expectations of Federal Reserve interest rate hikes.

The dollar index, which measures the greenback against a basket of currencies including the yen and the euro, was a shade higher at 101.36. It is now on track for a 2.5% gain for June, which marks the biggest monthly advance since July last year, Reuters reported.

The euro was flat at $1.1387 after hitting a 13-month low against the dollar last week, and was on track for a 2.3% monthly decline. Sterling traded 0.1% lower at $1.3198 and was down 2% for the month. The Japanese yen last traded at 161.75, continuing to langu...