The unnamed official's comments were carried by Syrian state TV a day after the USA -led coalition said a US airstrike had struck pro-Syrian government forces that the coalition said posed a threat to American troops and allied rebels operating near the border with Jordan.
On Thursday, the US sent aircraft to strike Syrian regime vehicles that violated a "deconfliction" zone set up around al-Tanf, an army base where USA and allied special forces are training Syrian militias, CBS News national security correspondent David Martin reported.
"This brazen attack by the so-called global coalition exposes the falseness of its claims about fighting terrorism", the source said.
United Nations special envoy Staffan de Mistura has agreed to put his proposal for a Syrian constitution on hold in order to stop the sixth round of Geneva peace talks being derailed by withdrawals and walkouts less than a week into proceedings.
"In every meeting we remind the attendees that there is terrorism by terrorists and also terrorism by states committed against our country", Mr al-Ja'afari said.
Syria on Friday condemned a US-led coalition strike on pro-government forces as a "brazen attack" and said it would "not be intimidated" after the surprise assault.
Russia, a main backer of Assad, also denounced the airstrike.
"We are deeply anxious about the erosion of the emerging understanding of the need to combine efforts of all those who confront terrorists" such as the IS and al-Qaida's branch in Syria, Lavrov said.More news: Oh Snap! Shares drop 25 percent after disappointing results
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"Any real effort to combat terrorism and to limit the Iranian influence.is in the interest of the Syrian people and the people of the region and worldwide peace and security", said Nasr Hariri, who represents the opposition at the Geneva talks.
Representatives of Syria's government and opposition High Negotiations Committee are in Switzerland for the sixth round of UN-backed peace negotiations, but there has been little sign of progress. Hariri said the government is not serious about discussing the political process of transition.
A US Pentagon official stated that the convoy was attacked by an air strike in the southern region of the country near the Jordanian border.
"They were potentially probing to see how close they could get to al Tanf", an anonymous U.S. official said. The source added that a number of people were killed in the attack.
Syrian state media gave no precise toll in the attack, but the Syrian Observatory for Human Rights, a Britain-based monitor, reported eight killed "most of them non-Syrian".
"This distracts us from the Syrian settlement and the major goal of this settlement - preventing the seizure of Syria and other parts of the Middle East by terrorists", Lavrov said.
The military media outlet added that the Americans had asked the Russian Federation to pressure the Syrian army to stay 15 kilometers (9 miles) away from their "illegitimate bases in Tanf". "The US Congress [House of Representatives], as you know, has already passed a bill that calls for punishing all those who cooperate with the legitimate government of Syria", Lavrov said. "And that is a coalition element made up of more than just USA troops, and so we will defend ourselves (if) people take aggressive steps against us".