Police found and defused two rockets pointed toward Pakistan's parliament and the president's official residence.
Pakistani officials say the two rockets were discovered early Thursday near the National Assembly building in downtown Islamabad.
Bomb disposal experts defused both rockets as security officials cordoned off the entire area.
Police say cellphones were attached to both rockets, prompting speculation of a possible remote-controlled attack.
The head of counter-terrorism at Pakistan's interior ministry, Brigadier General Javed Cheema, described the perpetrators as the same terrorists Pakistan has been confronting since joining the U.S.-led war against terrorism.
He downplayed the significance of the foiled attack and the weapons discovered at the scene.
"I think one really does not expect much damage from this kind of rocket," he said. "It is basically a weapon of harassment I would say."
Who the alleged terrorists may have been trying to harass remains unclear.
The rockets were found in a small construction site across the street from a cluster of government buildings, including the national parliament and the presidential palace.
The parliament was not in session.
General Cheema says a full investigation is under way and several suspects have been taken in for questionsing.
The rocket launchers were discovered just a day after a mysterious explosion occurred near the president's home in neighboring Rawalpindi. No one was injured in the blast, which military officials say was caused by a small explosive device.
Local authorities say President Pervez Musharraf was not the intended target and the attack was unrelated to his residence.