* Saudi's PIF indirectly supporting stocks - sources
* Saudi set to sign deals worth $50 bln at conference
* Saudi Industrial Export outperforms index after results
* Dubai's DP World reverses losses
By Abinaya Vijayaraghavan
Oct 23 (Reuters) - Saudi Arabia's market fell sharply after a volatile day of trading on Tuesday, as foreign and retail investors continued to sell despite efforts from state-backed funds to limit the fallout from the killing of Saudi journalist Jamal Khashoggi.
The main index slid 1.3 percent after recovering some of its losses earlier in the session.
The market weakness came on a day when a three-day investment conference opened in Riyadh that has seen a boycott by Western politicians and global chief executives in the wake of Khashoggi's killing.
Last week, foreign investors sold $1.07 billion in Saudi stocks, the biggest sell-offs since the market opened to direct foreign buying in mid-2015.
"The recent sell off has exposed some value but with all the turbulence and volatility, there is zero visibility on how things will progress and at this stage, we're not calling this a buying opportunity," Nick Wilson, chairman of London-listed Gulf Investment Fund plc, said.
The wider investment community is going to hold back from building a meaningful position until there is clarity on the current events, Wilson added.
But government-linked funds have been propping up Saudi Arabia's stock market since Oct. 14, when the index lost up to 7 percent in its biggest drop since December 2014. The index is down 5 percent in the month-to-date.
The kingdom's Public Investment Fund (PIF) has been indirectly supporting local stocks, using local institutions, to limit a market crash caused by the Khashoggi case, Reuters reported on Tuesday, citing sources familiar with the matter.
Nonetheless, Saudi Arabia was also set to sign deals worth $50 billion on Tuesday at the conference.
Saudi Arabian Mining (Ma'aden) rose 6.1 percent after it signed a contract with South Korea's Daelim Industrial to build an ammonia plant for about 3.35 billion riyals ($892.98 million).
Saudi Industrial Export outperformed the market, jumping 9.9 percent after its third-quarter loss narrowed.
Jabal Omar Development also advanced 3.7 percent after posting a third-quarter profit.
Egypt's blue-chip index lost 0.5 percent with Abu Qir Fertilizers and Chemical Industries falling 8.7 percent and Alexandria Mineral sliding 11.7 percent.
In Dubai, Amanat Holdings added 2.7 percent and Gulf Navigation Holding climbed 3.7 percent after Dubai Financial Market said direct deals were executed on 82 million shares of the company for 80.4 million dirhams.
The main index was up 0.2 percent.
Nasdaq-listed DP World reversed losses to rise 4.8 percent despite reporting a 6.7 percent drop in its shipping container volumes for the third-quarter.
The Abu Dhabi index inched up 0.3 percent with Arkan Building Materials jumping 12.9 percent and Emirates Driving Co rising 14.9 percent.
Ras Al Khaimah Cement increased 4.5 percent after its board approved the sale of a part in the firm's equity portfolio.
$1 = 3.7515 riyals SAUDI ARABIA * The index fell 1.3 percent to 7550 points. DUBAI * The index gained 0.2 percent to 2,753 points. ABU DHABI * The index added 0.3 percent to 4,970 points. QATAR * The index lost 0.1 percent to 10,264 points. KUWAIT * The index rose 0.5 percent to 5,172 points. BAHRAIN * The index was down 0.1 percent to 1,321 points. OMAN * The index was up 0.1 percent to 4,459 points. EGYPT * The index lost 0.5 percent to 13,580 points. Reporting by Abinaya Vijayaraghavan in Bengaluru; Editing by Alison Williams