All major Gulf stock markets opened higher on Sunday, extending their gains from the previous session, amid relief at no further escalation in tensions between Iran and the United States.

Last week, U.S. President Donald Trump backed away from days of angry rhetoric against Iran as the two countries tried to defuse a crisis over the U.S. killing of Iranian military commander Qassem Soleimani. 

Saudi Arabia's index rose 0.7%, outperforming regional peers and buoyed by gains in financial and petrochemical shares. Al Rajhi Bank and Banquet Saudi Francis were up 0.6% and 1.5%, respectively.

Advanced Petrochemical 2330.SE added 1.9% after reporting a 5.9% rise in estimated annual profit to 759 million riyals ($202 million). 

Saudi Aramco, however, was trading flat.

On Sunday, the oil giant said it had exercised its "greenshoe option" to sell an additional 450 million shares, raising the size of its initial public offering (IPO) to $29.4 billion. Aramco initially raised a then-record $25.6 billion in its IPO in December by selling 3 billion shares at 32 riyals. 

In Qatar, the index was up 0.3% as industries Qatar advanced 1% and Qatar Islamic Bank edged up 0.6%.

Dubai's index inched up 0.1% as blue-chip developer Emaar Properties gained 0.3%.

Amanat Holdings rose 2.3% after the healthcare and education investment firm said it was assessing a possible acquisition of a stake in the Middle East operations of VPS healthcare group. 

Abu Dhabi's index was also up 0.1%, with Emirates Telecom Group gaining 0.2%.

Kuwait's and Oman's stock markets are closed following the death of Oman's Sultan Qaboos bin Said and will resume trading on Tuesday and Wednesday respectively.

($1 = 3.7514 riyals)

(Reporting by Maqsood Alam in Bengaluru; Editing by Mark Potter) ((Maqsood.Alam@thomsonreuters.com;))