He said the Middle East is in such "chaos" that it has become a danger to international peace and security - and Syria "represents the most serious threat".
The UN chief told an emergency meeting of the UN Security Council that the highly volatile situation in the region risks "escalation, fragmentation and division as far as the eye can see, with profound regional and global ramifications".
"The Cold War is back - with a vengeance but with a difference," Mr Guterres warned.
He said the safeguards and mechanisms that managed the risk of escalation between the US and the Soviet Union in the past "no longer seem to be present".
Russia called the council meeting to focus on the threat to international peace and security from possible military action against Syria by the United States and its allies.
But the secretary-general took a much broader view of the often-interlinked factors escalating the chaos and threatening peace in the Middle East.
Mr Guterres cited the Palestinian-Israeli divide, the Sunni-Shiite divide "evident from the Gulf to the Mediterranean," opposing attitudes on the Muslim Brotherhood and the status of the Kurds, threats to communities that have lived in the region for millennia, and other factors.
"This multiplicity of divides is reflected in a multiplicity of conflicts with different degrees of interconnection, several of them clearly linked to the threat of global terrorism," he said.
Mr Guterres warned that "many forms of escalation are possible".
In Yemen, which faces the world's worst humanitarian crisis, Mr Guterres called for a negotiated political settlement to the three-year stalemated war that has killed more than 10,000 people.
He said it is also "high time to end the Libyan conflict" and he said it is "absolutely essential" to avoid a new conflict between Israel and Lebanon's Hezbollah militia which could be more deadly and destructive than the last war.
On Syria, Mr Guterres said: "We see confrontations and proxy wars involving several national armies, a number of armed opposition groups, many national and international militia, foreign fighters from everywhere in the world, and various terrorist organisations." He singled out "recent confrontations" between Iran and Israel in Syria.
In this "bleak panorama," the secretary-general said he was "outraged" by continued reports of chemical weapons use in Syria.
He strongly backed the Organisation for the Prohibition of Chemical Weapons' fact-finding mission to investigate last weekend's suspected poison gas attack in the Damascus suburb of Douma, saying the first OPCW team is already in Syria and "a second is expected today or tomorrow".
The secretary-general urged the deeply divided Security Council, which has been paralysed over Syria, to agree on a new body to determine responsibility for chemical attacks.
Increasing tensions and the inability to reach a compromise "threaten to lead to a full-blown military escalation," Mr Guterres warned, and risk "that things spiral out of control".
Additional reporting by the Press Association
