UNITED NATIONS — In sharp departure from his predecessor, Secretary-General Ban yesterday sided with President Bush and cautioned against “abrupt withdrawal” of American troops from Iraq, the course favored by the administration’s toughest Washington opponents.

Speaking at a press conference here, Mr. Ban also added his name to a list of would-be facilitators of peace talks between Israel and Syria, even as Jerusalem officials said the nature of regime of the Syrian president, Bashar Al-Assad — rather than the identity of the mediator — is the stumbling block to peace.

Mr. Ban, who is expected to meet Mr. Bush in Washington today and travel to San Francisco later this month, said he was reluctant to “inject myself” into the political clash between the American people, Congress, and the White House over Iraq. The decision, he said, “is up to President Bush and the United States administration, in close coordination with the American Congress.”

Nevertheless, he added, “I would like to tell you that great caution should be taken for the sake of the Iraqi people. The international community cannot and should not abandon them. Any abrupt withdrawal or decision may lead to a further deterioration of the situation in Iraq.”

Mr. Ban declined to say if he agreed with the assessment of his predecessor, Kofi Annan, that the Iraq war was “illegal.” He also rejected a criticism that he was “too close” to America, saying he was also close to other member states. Recent reports of secret negotiations between Israel and Syria in the Hebrew and Arab press, as well as periodic official statements about the prospects of an agreement to end the official state of war between the countries, have raised speculations about a new diplomatic movement. Alternatively, military maneuvers on both sides of the border have raised the specter of a possible clash of armies, even as both sides said they were not interested in war. “It is encouraging that Israel has expressed the willingness to talk with the Syrian president, and all other regional players,” Mr. Ban said yesterday. “As secretary-general, as well as the United Nations firmly supporting such initiatives, I would be happy to facilitate such peace initiatives.”

He referred to last week’s invitation by Prime Minister Olmert of Israel to Mr. Assad for face-to-face negotiations. Since then, however, Mr. Assad has rejected the invitation, and Foreign Minister Tzipi Livni of Israel dismissed reports of a secret negotiating track between the two countries.

“Many good people have proposed that they can facilitate between Israel and Syria,” Israel’s Foreign Ministry spokesman, Mark Regev, told The New York Sun yesterday. “The problem is not facilitation, rather the anti-peace policies of the regime in Damascus.” The Assad regime, he noted, has made alliances with such “anti-peace” and “violent” players as Iran, Hamas, Hezbollah, and the Islamic Jihad.

“Israel wants peace with Syria,” Mr. Regev said, but “it is very difficult to take Syria seriously as a partner of peace when they have chosen such partners.”

Mr. Ban’s special envoy to the Middle East, Michael Williams, told the Reuters news agency last week that major issues between the two countries “were pretty much thrashed out” in talks that took place in 2000. “So if negotiations were resumed, then maybe we could make real progress.” But, he added, Syria’s assessment that a deal was “in the drawer” was “somewhat exaggerated.”

Meanwhile, Syria last week removed roadblocks between Damascus and the Golan Heights for the first time since the 1973 war between the two countries, and also purchased new mid-range and long-range missiles that are capable of hitting most major Israeli cities. The Israel Defense Force conducted military exercises near the border of the two countries.