Saudi Arabia's benchmark index rose on Tuesday, while the Dubai bourse fell and was on course to extend losses for a fourth session as traders assessed lower oil prices and concerns over the U.S. government's debt-ceiling negotiations.

Oil futures traded sideways after mostly weaker-than-expected data from China muddied the outlook for demand from the world's top crude importer while U.S. plans to refill its Strategic Petroleum Reserve (SPR) underpinned prices.

However, an 18.9% rise in China's oil refinery throughput in April to the second highest on record helped keep a floor under crude prices.

Saudi Arabia's benchmark index gained 0.6%, with Dr Sulaiman Al-Habib Medical Services rising 1.7% and Al Rajhi Bank adding 0.8%.

Saudi Pharmaceutical Industries and Medical Appliances Corp jumped almost 10% following a surge in first-quarter earnings.

Dubai's main share index dropped 0.4%, hit by a 1.3% fall in blue-chip developer Emaar Properties and a 1.6% decline in Dubai Electricity and Water Authority .

In Abu Dhabi, the index was down 0.2%.

U.S. President Joe Biden and Republican House of Representatives Speaker Kevin McCarthy on Monday prepared for critical debt-ceiling talks, with a little more than two weeks to go before the U.S. government could run short of money to pay its bills.

A first-ever U.S. default would plunge the country into recession and inject chaos into global financial markets, economists said, and the standoff has started to worry investors and consumers.

The Qatari benchmark edged 0.1% higher in a choppy trade, with Islamic lender Masraf Al Rayan climbing 0.8%.

(Reporting by Ateeq Shariff in Bengaluru; Editing by Sherry Jacob-Phillips)