Oil futures closed higher Tuesday, but surrendered most of their gains from earlier in the session, ahead of a report that’s expected to show another increase in crude supplies.

Meanwhile, news that Iran seized a cargo ship traveling through a major shipping channel raised concern about the potential for disruptions to oil transport in the Middle East, but a pledge from Saudi Arabia’s deputy oil minister, Prince Abdulaziz bin Salman, to keep pumping oil inspired worries that the global glut of crude inventories will continue. But oil found support on the back of a weaker dollar. June crude settled at $57.06 a barrel, up 7 cents, or 0.1%, on the New York Mercantile Exchange but well below the session’s high of $57.83.

June Brent crude on London’s ICE Futures exchange fell 19 cents, or 0.3%, to $64.64 a barrel. “Oil prices enjoyed a speculative bounce on the earlier reports about Iran’s actions in the Persian Gulf,” said Richard Hastings, macro strategist at Global Hunter Securities. “But the rest of the story was less provocative and left the market thinking more about hedging and storage” than issues in the Strait of Hormuz. News reports said Iranian forces seized a commercial cargo vessel that was traveling through the major shipping channel.

At the same time, U.S. dollar weakness provided some support for oil.

The ICE U.S. dollar index fell Tuesday as traders looked ahead to a statement from Federal Reserve policy makers, expected after the conclusion of their meeting on Wednesday. Commodities priced in dollars often trade inversely with the greenback, as moves in the U.S. unit can influence the attractiveness of those commodities to holders of other currencies. “The potential for a dovish FOMC announcement [on Wednesday] could further increase oil prices,” said Jason Rotman, president of Lido Isle Advisors.

West Texas Intermediate crude on Nymex has been “consolidating” between $56 and $58 since mid-April, and our next upside target is $60, he forecast. “The oil market has likely passed through the worst period, but it is not out of the woods yet,” analyst Michael Cohen at Barclays Research said. Supply-and-demand fundamentals remain weak, and prices are likely to bounce in the range of $55 and $75 a barrel, he said.

Barclays however, raised its oil-price forecast by $8 on the back of Middle Eastern geopolitical unrest, new oil field outages and lower U.S. natural-gas prices. It now expects Brent crude to average $60 a barrel in 2015, and $68 a barrel in 2016.

Late Tuesday, markets will be tracking initial U.S. oil-inventory data from the American Petroleum Institute. The Energy Information Administration will release its weekly supply figures on Wednesday. Analysts polled by Platts forecast an increase of 1.4 million barrels in crude stockpiles.