U.S. stocks advanced on Monday, with the Dow Industrials up roughly one percent, as the threat of an escalation of tensions in Ukraine appeared to wane 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.

However, 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 continued to flourish and provide a lift to equities.

Discount retailer Dollar General Corp (DG.N) offered to buy Family Dollar Stores Inc (FDO.N) for $8.95 billion, trumping an offer by Dollar Tree Inc (DLTR.O). Family Dollar shares gained 5.1 percent to $79.91 while Dollar General jumped 9.8 percent to $63.07 as the two best performers on the S&P 500. The S&P retail index .SPXRT climbed 1 percent.

"People left Friday unsure of whether or not the Ukrainian conflict was escalating and they seem to have come back today thinking it's not," said Rick Meckler, president of LibertyView Capital Management in Jersey City, New Jersey.

"That has been the major driver, but then you have the usual suspects of what has supported this market all along - a somewhat improving economy and continued M&A activity, giving people confidence that higher stock prices are here to stay."

Housing stocks moved higher after the NAHB/Wells Fargo Housing Market index showed homebuilder sentiment rose to 55 in August, its highest level since January, from 53 in July. The PHLX housing sector index .HGX climbed 1.3 percent.

The Dow Jones industrial average .DJI rose 161.92 points or 0.97 percent, to 16,824.83, theS&P 500 .SPX gained 15.6 points or 0.8 percent, to 1,970.66 and the Nasdaq Composite.IXIC added 38.32 points or 0.86 percent, to 4,503.25.

Procter & Gamble Co (PG.N) is working with advisors, including Goldman Sachs Group (GS.N), as the world's largest household products maker reviews up to 100 underperforming brands for potential divestiture, people familiar with the matter said. P&G shares were up 1 percent to $82.64.

In a relatively light week for economic data, investors will closely monitor the Aug. 21-23 annual meeting of top central bankers at Jackson Hole, Wyoming, for possible insight about the path for monetary policy.

Minutes from the Federal Reserve's July meeting will be released on Wednesday.

Earnings season will effectively draw to a close this week with results from retailers including Home Depot (HD.N), Target Corp (TGT.N) and Gap Inc (GPS.N).

According to Thomson Reuters data through Monday, of the 467 companies in the S&P 500 that have reported earnings, 67.9 percent have topped analyst expectations, besting the 63 beat rate since 1994 and the 67 percent rate for the past four quarters.