Asian shares eked out modest gains on Tuesday as buyers were held back by persistent global cost pressures, with investors turning their focus this week to U.S. inflation data and the prospects for further aggressive Federal Reserve rate hikes.

Oil prices pulled back slightly on Tuesday on the latest progress in last-ditch talks to revive the 2015 Iran nuclear accord, which would clear the way to boost its crude exports in a tight market.

The U.S. dollar edged lower in early European trade Tuesday, adopting something of a holding pattern ahead of the release of the key U.S. consumer inflation data.

 Consumer expectations for US inflation over the coming years declined sharply in the latest survey by the Federal Reserve Bank of New York, a finding that may ease the Fed’s concern about ever-rising prices getting baked-in to household behavior.

Investor morale in the euro zone was essentially unchanged in August from the previous month, with a slight rise too little to stave off fears of recession in the 19-country currency bloc, a survey showed on Monday.

Taiwan's exports rose in July on sustained demand for technology products with shipments to China picking up, and while the government said the outlook was good for semiconductors it warned of growing uncertainly for the global economy.