US STOCKS-Wall St to open up as Ukraine worry lessens, M&A boost
* Dollar General offers to buy Family Dollar
* Russia says humanitarian convoy issue resolved, but no ceasefire
* Futures up: Dow 81 pts, S&P 9.5 pts, Nasdaq 18.75 pts (Updates prices)
By Chuck Mikolajczak
NEW YORK, Aug 18 (Reuters) - U.S. stocks were poised for a higher open on Monday, as the threat of an escalation in Ukraine appeared to lessen and the latest flurry of merger action supported equities.
* Russia said all issues related to its humanitarian convoy to Ukraine had been resolved but said no progress has been made toward a ceasefire or political solution to the fighting in the east of the country after talks between Russia, Germany, France and Ukraine on Sunday.
* The region remained unsettled as Ukraine accused pro-Russian rebels on Monday of hitting a refugee convoy of buses with rocket fire near the eastern city of Luhansk, but the separatists denied responsibility.
* Mergers and acquisitions continue to flourish and provide a lift to equities. Discount retailer Dollar General Corp offered to buy Family Dollar Stores Inc for $8.95 billion, trumping an offer by Dollar Tree Inc. Family Dollar shares gained 4.9 percent to $79.90 before the opening bell while Dollar General jumped 10.1 percent to $63.25.