The veteran leader, in power for 32 years, accused the parliamentary opposition of wanting to "seize power through the blood of youths".
Protests against Saleh intensified after a March 18 bloodbath when regime loyalists gunned down 52 people outside Sanaa University, sparking widespread international condemnation and a string of anti-regime defections.
While a massive crowd protested against Saleh's regime in Sanaa last Friday, the 69-year-old president's loyalists staged a huge counter-demonstration of his supporters.
Saleh on Monday accused "Al-Qaeda, the Huthis (Shiite Zaidi rebels of north Yemen), separatists" in the south and the parliamentary opposition of ganging up against his regime at the expense of Yemeni stability and security.
A declared ally in the US battle against Islamist militants, Saleh is grappling with anti-regime protests which have divided the army, a secessionist movement in southern Yemen, and a resurgent Al-Qaeda.
His remarks came after Washington warned on Sunday that the fall of Saleh would pose a "real problem" for the United States.
"I think it is a real concern because the most active and at this point perhaps the most aggressive branch of Al-Qaeda, Al-Qaeda in the Arabian Peninsula, operates out of Yemen," said US Defence Secretary Robert Gates.
A top opposition figure in parliament, Mohammed Sabri, said: "The US defence minister's exaggeration of Al-Qaeda has encouraged the regime."
But the US ambassador to Yemen, Gerald Feierstein, has held talks with two leading figures who have defected, sources close to both men told AFP on Tuesday.
Feierstein met on Monday with General Ali Mohsen al-Ahmar, commander of the military's northwest region which covers Sanaa, and Sadiq al-Ahmar, head of the Hashid tribal federation, the largest in deeply tribal Yemen.
Meanwhile, negotiations with the president on a transition have been suspended since last Thursday, according to Sabri. "Saleh is shirking his commitments, and negotiating with him is useless," he said.
Saleh himself called for "those wanting power to head to the polls".
Last week, he reportedly offered to step down by the end of 2011, a proposal snubbed by the opposition. But his ruling party said Friday he should serve out his current term until the next scheduled presidential election in 2013.
With the political showdown in limbo and tensions running high across the impoverished country, the death toll of a massive blast and fire at an ammunition plant looted by Al-Qaeda has shot up to 150, local officials said.
In Sanaa late on Monday, a son-in-law of the president, Yahya Mohammed Ismael, joined the protesters camped at the square near the university since February 21.
And a dozen army officers joined the protesters at the square at the same time, according to the AFP correspondent.
Saleh has sacked and replaced the army commander for Yemen's eastern region, General Mohammed Ali Mohsen, who has also joined the anti-regime camp, according to the defence ministry's 26sep.net website.