Prime Minister Tayyip Erdogan said on Friday relations between Turkey and the United States are in danger over a resolution branding as genocide massacres of Armenians by Ottoman Turks during World War One.
Referring to ties with the United States and the Armenian bill, Erdogan, with a Turkish idiom used to describe relations, said: "Where the rope is worn thin, may it break off."
The crowd of supporters broke into applause.
Ankara is a crucial ally in the region for Washington, which relies on Turkey as a logistical base for the war in Iraq. But U.S. popularity has hit rock bottom in Turkey because of the war and perceptions that the United States is failing to stop Turkish Kurdish rebels using north Iraq as a base from which to attack Turkey.
"This is as much about domestic politics in Turkey as it is in the United States," Turkish commentator Semih Idiz said.
"There is a lot of brinkmanship. There is pressure on House speaker Nancy Pelosi to fight the Bush administration."
Before the approval of the resolution by the U.S. House of Representatives Foreign Affairs Committee on Wednesday, relations had already been undermined by Ankara's plans for a possible incursion into northern Iraq to tackle the rebels.
Some analysts say the Armenian bill would make the incursion more likely, as Ankara will feel less restrained by Washington's calls for caution.
Commentators said Erdogan's comments on Friday showed how concerned Turks were about the situation.
"I would say he's half serious. He's genuinely concerned about relations," said columnist Burak Bekdil. "It reflects his concern about domestic thinking on ... this fiasco."
Ankara has called back its ambassador for consultations over the bill, which now has to go to the House floor.
Turkey denies a genocide was carried out, saying Turks and Armenians were killed in World War One as the Ottoman Empire collapsed. Charges of genocide, backed by Armenians and several countries' parliaments, are seen as a national insult.
"With this whole Armenian and Kurdish thing he has to play nationalistic," said leading commentator Mehmet Ali Birand. "He is doing it just for his image, for public opinion, to show it's not just the military that's tough ... he's tough as well."
The influential and popular army has been calling for a green light to go into northern Iraq to crush rebel bases.
The United States and the European Union have cautioned against such an operation, fearing it will destabilize Iraq's most peaceful area and potentially the wider region.
But Turkey is becoming frustrated as the number of soldiers killed continues to rise, reaching 30 in the past two weeks.
Kurdish separatist rebels said on Friday they were crossing back into Turkey to target politicians and police after Ankara said it was preparing to attack them in northern Iraq.
"We don't need anyone's advice on northern Iraq and the operation to be carried out there," Erdogan told the crowd, to loud applause, having earlier said the United States "came tens of thousands of kilometers to attack Iraq without asking anyone's permission".
Turkish-U.S. relations were stable during the Cold War. Ties have become more complicated in recent years as Turkey's political landscape has dramatically changed.
The ruling AK Party with roots in political Islam came to power in 2002 and has set about revitalizing foreign policy and paying more attention to playing a role in the Middle East.
Relations hit a low in 2003 when parliament rejected a U.S. request to use Turkish territory in the invasion of Iraq.
The AK Party has, however, also secured European Union accession talks status and in recent years both Washington and Ankara have sought to improve ties.