SINGAPORE: Oil prices were mixed in Asian trade Tuesday as investors weighed the eurozone's mounting debt woes with the prospect of a disruption to Middle East supplies, analysts said.

New York's main contract, West Texas Intermediate crude for delivery in July was up 23 cents at $91.09 per barrel while Brent North Sea crude for July shed 10 cents to $107.01 in morning trade.

“Oil prices continue to remain under pressure... with the lack of concrete measures from European policymakers to address the Greek issue weighing heavily on the market,” Barclays Capital's analysts wrote in a commentary.

Markets also recoiled on fears that Spain -- the eurozone's fourth largest economy -- would follow Greece, Ireland and Portugal and ask for a bailout after yields on it bonds shot up Monday.

The rise comes amid investor concerns about the state of the country's banking sector after one of its biggest lenders, Bankia, asked for $24 billion in state aid.

But while Prime Minister Mariano Rajoy said the banking troubles would have no impact on efforts to trim the public deficit and denied that it had undermined confidence in Spanish sovereign debt.

Meanwhile, investors are also keeping close watch on the situation in Iran, after the Islamic republic and Western powers failed to reach an agreement on Tehran's nuclear programme, which is thought to mask a nuclear weapons push.

Despite the offer of incentives by the West, Tehran has refused to suspend enrichment of uranium to 20 per cent, insisting that it has the right to do so for peaceful purposes.

Iran has threatened to disrupt Middle East oil supplies if it is slapped with further sanctions by the West, while its arch-enemy Israel has not ruled out launching a pre-emptive strike on its nuclear facilities.

“In our view, any sign that the diplomatic track is stalling, or approaching a dead end, will invariably make the military option look more likely,” analysts from Barclays Capital said.