UNITED NATIONS — Secretary-General Ban is said to be weighing a plan to travel to Lebanon, where he will try to diplomatically untangle a political impasse that many in the country, as well as in key world capitals, believe can be solved only with increased international pressure.

Mr. Ban sees both the carnage in Darfur, Sudan, and the political knot in Beirut as two diplomatic priorities he can personally contribute to solving, according to officials familiar with his thinking. In both cases, he would confront despots at odds with U.N. Security Council resolutions: President Bashir of Sudan has denied entry to international troops attempting to protect civilians in Darfur; and Lebanese allies of President Al-Assad of Syria have blocked attempts to establish an international tribunal to try suspects in the 2005 assassination of a former prime minister of Lebanon, Rafik Hariri.

Last month, Mr. Ban asked the Security Council to hold off on imposing sanctions on Khartoum. More recently, he requested a delay in attempts by America and France, both permanent council members, to force a tribunal on Lebanon.

On the Lebanese issue, Mr. Ban “thinks the same way as he did about Darfur,” his spokeswoman, Michele Montas, told The New York Sun yesterday. “The solution cannot come from the outside. It has to come from within.”

She confirmed that Mr. Ban is contemplating a trip to Lebanon, “if he thinks his presence might make a difference.” As of yesterday, she added, “he has not made a decision” to go.

According to several diplomats and U.N. officials, Mr. Ban, who recently visited Mr. Assad in Damascus, hopes to negotiate with pro-Syrian politicians in Lebanon who so far have successfully blocked the international tribunal. Mr. Assad’s aides and family members have been mentioned by U.N. investigators as possible suspects in the Hariri assassination and subsequent political killings in Lebanon.

The American ambassador to the United Nations, Zalmay Khalilzad, said Lebanese politicians might already have reached an impasse. “If the judgment is made that the domestic thing cannot solve it — that’s our view at this point, and we have to convince others — then we’ll have to go to a resolution,” he told the Sun. “But I think the secretary-general’s judgment on that will be important as well.”

American and French diplomats are reportedly preparing a resolution under Chapter 7 of the U.N. Charter that would allow the council to establish the international tribunal even as the pro-Syrian opposition maintains its resistance.

America “will use every means at its disposal to further the pursuit of justice and to put an end to the current campaign of assassinations,” Secretary of State Rice wrote yesterday in an op-ed in Beirut’s a-Nahar newspaper.

But in recent days, officials of the pro-Syrian terror group Hezbollah hinted that it would use violence if such a resolution were passed. “We say no to the establishment of a tribunal under Chapter 7,” the organization’s leader, Sheik Hassan Nasrallah, told an Arabic-language Iranian TV channel.

Hezbollah and its Shiite political allies, as well as some pro-Syrian Maronite Christians, withdrew from Prime Minister Siniora’s Cabinet soon after the Security Council passed a resolution establishing the tribunal last November. The Beirut Cabinet later voted in favor of the tribunal, but Hezbollah politicians later prevented a parliamentary vote to ratify the decision. The political maneuvering has created a constitutional crisis, which is increasingly seen as threatening Lebanon’s independence.

A European diplomat who spoke on condition of anonymity said yesterday that policy-makers in Washington and Paris are concerned that by creating a false impression of a diplomatic process with the pro-Syrian forces in Lebanon, Mr. Ban may unwittingly encourage Mr. Assad’s allies on the Security Council, led by Russia, to resist a resolution under Chapter 7.