Powell reiterated US demands for leaders of Hezbollah, Hamas and Palestinian Islamic Jihad to be expelled from Damascus and said allegations that Syria was serving as a transit point for weapons for these organizations were troubling.
"Any participation in the shipment of weapons from anywhere through Syria to Palestinian terrorists is to be condemned," he told reporters at the State Department after meeting with Turkish Foreign Minister Abdullah Gul.
"Syria cannot be serious about wanting a better relationship with Israel, the United States or anyone else, as long as it serves as any kind of a trans-shipment point for weapons that are going to terrorists of the kind who killed innocent people this morning in Jerusalem," he said.
He referred to the suicide bombing earlier Thursday that killed 10 people and the attacker aboard a rush-hour bus close to Israeli Prime Minister Ariel Sharon (news - web sites)'s official residence in Jerusalem.
Syria had asked Turkish Prime Minister Recep Tayyip Erdogan, who is in Washington, to convey three messages to the United States, including its desire for a resumption of peace talks with Israel that broke down four years ago.
On Saturday, Erdogan said Ankara would be prepared to mediate between long-time enemies Israel and Syria.
Both countries gave a cautious welcome to the offer, but Sharon has said any negotiations are contingent on a halt to Syrian support for Palestinian and Lebanese militant groups.
Powell did not address the accuracy of charges that weapons have continued to flow through Syria to anti-Israel groups, but said he had not seen enough action from Damascus on suggestions he delivered to Syrian President Bashar al-Assad last May that would ease the US concerns.
"I haven't seen enough action on those steps," he said. "I hope that Syria will reflect on its position and start to take action to eject from Damascus the leaders of terrorist groups that make it hard for us to find a way forward between the Palestinians and Israelis.
"And I hope that Syria will look at all the other things we asked it to reflect upon to include possession of weapons of mass destruction," Powell said.
He has previously urged Syria to follow the lead of Libya in renouncing nuclear, chemical and biological weapons and throwing its facilities open to inspectors to verify that the programs have been dismantled.
Washington has also accused Damascus of helping to arm the ousted regime of Saddam Hussein (news - web sites) and of turning a blind eye to foreign militants entering Iraq (news - web sites) to carry out attacks on the US-led coalition.
Syria has vehemently denied US charges of supporting terrorism and developing weapons.
It also accuses Washington of double standards and not doing enough to rein in its close ally Israel, which remains in occupation of the Golan Heights, a strategic plateau seized from Syria in the 1967 Arab-Israeli war.
