The group has killed more than 800 people in four decades of armed struggle for independence of the Basque country, a region that has considerable autonomy within Spain.
The national election is currently scheduled for March 2008.
Vote on time
On Wednesday, Zapatero ruled out any early vote as he spoke at a news conference with Ban Ki-moon, the UN secretary-general, saying: "The elections will he held when they are due to be held, when the four-year term ends in March."
The Socialist prime minister said one of his main goals now is to forge a common front against Eta with the Conservatives.
The latter have criticised him for negotiating with the group after it called the ceasefire in March 2006 and refusing to rule out more talks even after Eta set off a bomb at Madrid airport in December, killing two people.
Eta said on Tuesday that "the minimum conditions for continuing a process of negotiations do not exist".
It said the Zapatero government had responded to its ceasefire "with arrests, torture and persecution".