WASHINGTON (Reuters) - Growing signs of an economic slowdown and escalating trade confrontations between the United States and China have caused global oil demand to grow at the slowest pace since the global financial crisis in 2008, the International Energy Agency said on Friday.

`` The situation is getting more uncertain, and the growth of global oil demand has been very slow in the first half of 2019, '' the Paris-based agency said in its monthly report.

When compared with the same month of 2018, global demand fell by 160,000 barrels per day in May, marking the second year-on-year decline in 2019.

From January to May, oil demand rose 520,000 barrels per day, the smallest increase since 2008.

"Prospects for a political deal between China and the United States on trade have deteriorated," the agency said. "This could lead to shrinking business activity and lower growth in oil demand."

The agency lowered its forecast for global demand growth for 2019 and 2020 to 1.1 million barrels per day and 1.3 million barrels per day respectively, noting that China is the only major source of growth by 500 thousand barrels per day in the first half of this year.

She noted that demand growth in the United States and India reached only 100,000 barrels per day in the period from January to June last.

"The outlook is fragile with a greater likelihood of a downward revision than a revision," the report said.

Meanwhile, supply constraints imposed by the Organization of the Petroleum Exporting Countries (OPEC) and its allies are causing market scarcity and slowing non-OPEC production.

But the IEA says the balance will be temporary. It expects strong non-OPEC production growth in 2020 at 2.2 million barrels per day, and predicts the global oil market will have "good supplies."

The agency said that economic concerns dominate geopolitical factors, but the oil market is still closely following tensions between the United States and Iran.

US sanctions on Iran pushed Tehran's crude oil exports down in July by 130,000 bpd to 400,000 bpd, the lowest level since the 1980s.

Oil prices rose yesterday as they received some support from expectations of further OPEC production cuts, although concerns about the long-running trade dispute between the United States and China are holding back gains.

Brent crude futures were at $ 57.54 a barrel, up 16 cents, or 0.3 percent, from the previous settlement. US West Texas Intermediate (WTI) crude futures were at $ 52.68 a barrel, up 14 cents, or 0.3 percent, from the previous close.

Brent and WTI crude futures rose more than 2 percent on Thursday on reports that Saudi Arabia, the world's biggest oil exporter, had invited other producers to consider the recent drop in crude prices.

Oil prices are still down more than 20% from their peak in April.

Global financial markets have been shaken over the past week after US President Donald Trump said he would impose a 10 percent tariff on more Chinese goods from September as the yuan's decline fueled concerns about a currency war.

In the meantime, a Saudi oil official said that the Kingdom, the largest crude producer in the Organization of Petroleum Exporting Countries (OPEC), plans to keep crude oil exports at less than seven million barrels per day in August and September to rebalance the market and contribute to the reduction of global oil stocks .

UAE Energy Minister Suhail Al Mazrouei said the UAE would continue to support measures to balance the oil market.

He added that the joint ministerial monitoring committee of OPEC and non-OPEC producers will meet in Abu Dhabi on September 12 to review the situation in the oil market.