UNITED NATIONS – Secretary-General Annan called Syria’s President Assad yesterday, expressing concerns about possible confrontation between Israel and the terrorist group Hezbollah. Earlier, Mr. Annan also spoke to Lebanon’s Premier Siniora and Israel’s acting Prime Minister Olmert.

Mr. Annan’s call to Damascus was meant to thank Mr. Assad for his reported cooperation with the investigation into the assassination of the former Lebanese prime minister, Rafik Hariri, and to urge him to continue to cooperate. But Israeli diplomats said the call was also part of their own effort to convey a message to Mr. Assad through intermediaries that Jerusalem would hold him responsible for any Hezbollah attacks.

Serge Brammertz, the Belgian charged by the United Nations with investigating the murder, yesterday reported to the Security Council on his attempts to secure interviews with Syrian officials. “We will see if our cautious optimism is justified or not,” Mr. Brammertz told reporters afterward.

The February 2005 Hariri killing took place shortly after a Security Council resolution called on all foreign forces to leave Lebanon. Although Syrian troops have withdrawn from the country, they remain, along with Iran, the main benefactors of Hezbollah, which has defied the council by remaining armed.

During his phone conversation with Mr. Assad yesterday, Mr. Annan expressed his concerns over the situation on the Lebanese-Israeli border, a U.N. spokesman, Stephane Dujarric, told The New York Sun. The secretary-general specifically told Mr. Assad that U.N. observers in southern Lebanon reported to him on “heightened tensions and a possible confrontation along Israel’s northern border,” Mr. Dujarric said.

The increased Hezbollah threat around Israel’s border in the last 48 hours might be related to the pressure on Syria in the Hariri investigation, diplomats said. Other events in the region, including anger over Israel’s arrest of Palestinian Arab murder suspects in Jericho on Tuesday, and most prominently the Security Council’s diplomacy on Iran’s nuclear aspirations, also were seen as linked to the high tension in the region.

“Syria and Iran are one camp – an alliance of evil,” Israel’s ambassador in Washington, Daniel Ayalon, told the Sun. “There is a lot of diplomatic pressure on them, and on their Lebanese ally, Hezbollah, and increasingly on Hamas as well. Their actions could be seen in the context of their growing isolation.”

A diplomat at the United Nations, who spoke on condition of anonymity, acknowledged the possibility of a link between the events. “We are concerned that if one of these fronts ignites, it could lead to a major regional escalation,” he said.

Israeli troops raised the troop alert level on the northern border yesterday. “We have received specific information that Hezbollah is planning an attack,” a Foreign Ministry spokesman, Mark Regev, said. Residents of towns along the border were instructed to take special care, he said, and remain indoors. The main concern is that Hezbollah operatives might attempt to kidnap Israeli soldiers to turn them into bargaining chips.

“We know Hezbollah could not be acting in such an irresponsible manner if not for the green light from Damascus,” Mr. Regev said.

Under pressure, Syria has agreed that Mr. Assad and Foreign Minister Farouk al-Sharaa would meet with Mr. Brammertz and his team of investigators, Mr. Assad told Britain’s Sky News yesterday. “In the meeting they can ask about anything, and we expect them to ask about the political background of the problem of the relations between Syria and Lebanon,” he said. But he insisted the meeting was “not for interrogation.”

Mr. Brammertz’s report, officially given yesterday to council members, reflects a “shift from a more investigatory stage to a stage more characteristic to trial preparation,” American U.N. Ambassador John Bolton said. As for Syria’s reported willingness to cooperate with the investigation, he said, “Agreement in principle doesn’t mean anything. Performance is what we are looking for.”

The 15 members of the council also met informally on Iran yesterday at the French mission, attempting to coalesce around a statement reaffirming previous resolutions of the International Atomic Energy Agency, and calling on its director, Mohamed ElBaradei, to report within a short time on the extent of Iran’s cooperation.

The council is expected to reconvene again Friday, but diplomats were skeptical yesterday that they could reach an agreed position before a Monday meeting in New York between Undersecretary of State Nicholas Burns and his counterparts from the foreign ministries of Russia, China, France, Britain, and Germany.

And just as he did on Tuesday, the Qatari U.N. ambassador, Nassir Abdulaziz al-Nasser, representing the Arab group, yesterday convened the council to convince its members to act on the Jericho prison raid. But according to Britain’s deputy ambassador, Adam Thomson, Mr. al-Nasser, after consulting with the Palestinian Arab observer Riad Mansour, obstructed the consultations, preventing any agreed statement between council members.

The Arab group is expected to convene the council again on this issue on Monday, this time for an open debate where the 15 members, as well as others, could vent anger against Israel. One exasperated diplomat said yesterday, “It seems that any time the council does anything on Iran, the Arab group tries to change the subject by talking about Israel.”