The developments in the southern Syrian border have been discussed between Jordan, the United States and Russia. The three parties agreed on the need to preserve a “de-escalation” zone they brokered last year and which has reduced violence, a senior official told Reuters on condition of anonymity on Monday. The official said the three countries that signed last year’s deal to create the zone “saw eye to eye” on the need to preserve it as a key step to “accelerate efforts to reach a political solution” in Syria. The truce — the first US peacekeeping effort in the war under Donald Trump’s presidency — has reduced violence in a particularly sensitive region that includes Syrian territory bordering Israel. Earlier, Russian Foreign Minister Serge Lavrov stressed that only Syrian regime forces should be on the country’s southern border with Jordan and Israel, after Washington warned of “firm measures” over truce violations in the region. Rebels control stretches of southwest Syria, bordering the Israeli-occupied Golan Heights, while regime troops and allied Iran-backed militias hold nearby territory. The United States has voiced concern about reports of an impending regime offensive in a “de-escalation zone” in the southwest, warning Damascus it would respond to breaches. “Of course, the withdrawal of all non-Syrian forces must be carried out on a mutual basis, this should be a two-way street,” Lavrov told a news conference on Monday. “The result of this work which should continue and is continuing should be a situation when representatives of the Syrian regime stand at Syria’s border with Israel,” he said.