Oil prices shed some of their massive gains on Friday taking stocks in Asia lower, as doubts grew over an oil price deal between Saudi Arabia and Russia that U.S. President Donald Trump said he had brokered.With the coronavirus pandemic raising the risk of a prolonged global downturn, investors continued to seek the safety of the U.S. dollar and government bonds, pushing U.S. Treasury yields near their lowest in three weeks.European stocks are expected to drop, with Euro Stoxx 50 futures down 0.26% while German DAX futures and FTSE futures both slipped about 0.3%.U.S. West Texas Intermediate (WTI) crude lost $1.18, or 4.7%, to $24.14 a barrel, having surged a record 24.7% on Thursday. Brent futures dropped $1.37, or 4.6% to $28.55.Trump said on Thursday he had spoken to Saudi Crown Prince Mohammed bin Salman, and expects Riyadh and Moscow to cut oil output by as much as 10 million to 15 million barrels, as the two countries signalled willingness to make a deal.Saudi Arabia said it would call an emergency meeting of the Organization of the Petroleum Exporting Countries, state media reported.The amount cited by Trump would represent an unprecedented cut equal to 10% to 15% of global supply, in output per day terms, a common unit of measurement.However, Trump provided few details, an omission some analysts said was likely intentional."He is a business man and smart enough to know these things. A cut of 10-15 million barrel per day (bpd) would be simply impossible," said Norihiro Fujito, chief investment strategist at Mitsubishi UFJ Morgan Stanley Securities.