The mediators hailed the accord as an important step forward in efforts to reduce tensions in the area, which sparked a brief but devastating war between the two last August, but diplomats warned that it needed to be tested on the ground.
"We think this is an important step to security and stability," European Union special representative for the issue Pierre Morel told a news conference, while United Nations mediator Johan Verbeke hailed "a significant first agreement."
However, U.S. Assistant Secretary of State Daniel Fried struck a note of caution, while agreeing the development in the fourth round of mediated talks between the two countries in Geneva since October, was "positive and practical."
"Putting it into effect will depend on goodwill on the ground on both sides," he told the news conference. The United States, which regards Georgia an ally in the volatile Caucasus region, attends the talks as an interested party.
In a formal statement, the three mediators, who also include a representative of the Organization for Security and Cooperation in Europe (OSCE), said the talks had produced by consensus "proposals for joint incident prevention and response mechanisms."
It said the mechanisms would allow for regular contacts "between structures responsible for security and public order in areas of tension and relevant international organizations."
The cautious wording covered both Russian and Georgian forces as well as police and other forces of South Ossetia, and another breakaway region, Abkhazia, which have declared independence and gained Russian recognition but are still regarded by Georgia as part of its territory.
The aim of establishing the mechanisms, details of which were not immediately released, was to "ensure a timely and adequate response to the security situation," including incidents and their investigation, the statement said.
Security forces of all parties would meet each week, more if necessary, and the first gathering would be held soon, it added.
Georgia's First Deputy Foreign Minister Giorgi Bakeria told a separate news conference that the move was "a step in the right direction," but insisted it should be followed by talks on full Russian withdrawal from "occupied Georgian territories."
There was no formal comment from Russian officials attending the talks. But continuing sharp differences separating the Georgians from the Russians were reflected in parallel talks over the past two days on humanitarian issues and refugees in the region.
Diplomats said the South Ossetians, citing security, had declined to accept the return of Georgians to homes in the region from which they had been driven by militias during and after last August's fighting, or to allow humanitarian convoys.
The Russians had also declined to set a date for the next round of talks, the diplomats said.
Morel said there had been agreement that the next round, when it takes place, would consider security arrangements such as the non-use of force and international presence in the region.