According to a state department transcript released on Tuesday, Condoleezza Rice, the US secretary of state, told the New York Times: "We'd like to get some others to join us in other kinds of sanctions [against Syria]."
Washington has long listed Syria as a "state sponsor of terrorism" and has accused it of fueling violence in Iraq.
In May 2004, Washington banned US exports to Syria other than food and medicine, severed banking relations with the Commercial Bank of Syria and barred Syrian flights to and from America.
Washington also recalled its ambassador to Damascus after the assassination of Rafiq al-Hariri, the former Lebanese prime minister, although Syria denies any involvement.
Rice said: "We're going to have to look at tougher measures if Syria continues to be on the path that it's on."
She gave no details on what sanctions the US might want to impose but Sean McCormack, the state department spokesman, said: "We have a variety of measures that are available to us."
Paying the price
Walid al-Moualem, Syria's foreign minister, told the UN General Assembly: "Tragically enough, we all end up paying the price when the decision makers in Washington believe that they know better, and are in a better position to understand and grasp the needs and circumstances of the Arabs.
"They diagnose the ambitions and aspirations of the Arab individual in a manner that is tailored to their own vision."
He criticised the US for its support of Israel and other policies in the Middle East, saying the flow of US weapons to Israel was sowing destruction.
He said: "The Palestinians are subjected to a crippling blockade because the advocates of democracy were dissatisfied with the results of the elections in the Palestinian territories."
The US and EU have imposed financial sanctions on the Hamas-led Palestinian government since it came to power in March.