Oil prices inched down on Tuesday, extending losses from the previous session, as investors sought clearer signs of progress toward restoring crude flows through the Strait of Hormuz following U.S.-Iran peace talks.

Brent crude ‌futures fell 20 cents, or 0.3%, to $77.70 a barrel, and U.S. West Texas Intermediate declined to $73.74 a barrel, down 12 cents, or 0.2%, as of 0323 GMT.

Prices fell more than 3% on Monday after the United States granted Iran a 60-day sanctions waiver following initial peace talks, and as officials reported a lull in hostilities in Lebanon under the broader agreement.

"The gradual increase in oil flows through the Strait of Hormuz continues to weigh ​on the market," said ING analysts in a note.

Two crude tankers with just under 2 ​million barrels of oil sailed through the Strait of Hormuz on Monday, ship-tracking data showed, in a sign that traffic was picking up following weaker flows on Sunday due to concerns over passage through the ​waterway.

"Transits over recent days look to have risen sharply, (which) the market will treat as a proxy ​for both physical oil, perhaps paper oil, and diplomatic progress," said Sparta Commodities' head of research Neil Crosby ‌in ⁠a note. "It feels like we will be stuck in this bearish risk-off/optimistic mood until such time as something changes."

The price declines come after a weekend that had appeared to put the week-old accord in jeopardy, including threats from U.S. President Donald Trump to restart the war if Iran ​disrupted shipping through the ​Strait of Hormuz ⁠after Tehran declared the strategic waterway closed.

"There remains a prevailing dose of market scepticism, rooted in deep-seated mistrust between Washington and Tehran, suggesting ​that any return to pre-war oil prices is likely to be ​delayed rather ⁠than immediate," said Tim Waterer, chief market analyst at KCM Trade.

Separately, analysts in a Reuters poll expect U.S. crude inventories to have fallen last week, along with distillate and gasoline inventories.

On Monday, government ⁠data ​showed U.S. crude stocks in the Strategic Petroleum Reserve fell to ​331.2 million barrels last week, the lowest since June 1983, as supplies tightened in the wake of the U.S.-Iran conflict.