The State Department has evacuated most of its diplomats from Lahore, Pakistan in response to a terrorist threat against the U.S. consulate, senior State Department and other senior U.S. officials told CNN.

"We have picked up what we regard as a threat worthy of taking this action," one senior U.S. official told CNN.

The State Department issued an "ordered departure" for all of its diplomats in Lahore Thursday, except for a handful of emergency personnel. The diplomats were moved to Islamabad, the nation's capital, officials said.

A travel warning issued by the State Department said the department "ordered this drawdown due to specific threats concerning the U.S. Consulate in Lahore" and warned U.S. citizens against travel to Pakistan.

"The presence of several foreign and indigenous terrorist groups poses a potential danger to U.S. citizens throughout Pakistan," the travel warning said.

Pakistan was not aware of any security threat against the Lahore consulate prior to the U.S. decision to transfer the diplomats to Islamabad, said Omar Hameed Khan, spokesman for Pakistan's interior ministry.

It was unclear whether the latest threat to the consulate was related to a current threat against U.S. facilities and personnel that prompted the United States to close diplomatic posts throughout the Middle East, Asia and Africa.

While one U.S. official said it was not related, a second U.S. official said the connection wasn't clear.

"We are still digging and trying to trace whether it is related," the senior U.S. official said about the possible link between the heightened threat against the U.S. in the region and the threat against the consulate in Lahore. "I'm not willing to say it's related, but can't say it is unrelated. We just don't have that level of granularity yet."

No U.S. diplomatic posts in Pakistan were closed as a result of the earlier warning.

Most of al Qaeda's core leadership is believed to reside in Pakistan, and the city of Lahore is home to other extremists sympathetic to the group. Lahore is well-known as a base for Lashkar-e-Tayyiba, which is considered a terrorist organization by the United States.

This week, the local government in the province of Punjab, where Lahore is located, tightened security measures, including police checkpoints at the city's entrance and exit points. Minister for Environment Protection Shuja Khanzada said the measures were taken after the government received intelligence reports of possible terror threats around the Eid al-Fitr holiday, which marks the end of Ramadan, the month of fasting.

Over the last decade, the United States has waged a persistent campaign against the terror threat in Pakistan, using drones and working with the Pakistani military and intelligence. While the country remains a hotbed of terrorism, President Barack Obama has touted the U.S. gains in fighting al Qaeda, which has been based there.

During an address to Marines at Camp Pendleton, California, Wednesday, Obama said that al Qaeda has been "decimated," making a distinction between the terror network's leadership and affiliates that are spread throughout the Middle East and parts of Africa.

"Because of you, Osama bin Laden is no more," Obama said. "Because of you, al Qaeda's top ranks have been hammered. The core of al Qaeda in Afghanistan and Pakistan are on the way to defeat."

Journalist Annabel Symington in Islamabad contributed to this report.