Pakistan’s capital, Islamabad, is in alert after a bomb exploded Sunday in a very popular Italian restaurant, killing a Turkish woman and wounding 11 other people.

The restaurant Luna Caprese is situated in a popular shopping area, also being one of the few places in the capital that serves alcohol. It is usually crowded with foreigners. Security officials think that the attackers had carefully planned the explosion, intentionally choosing a place usually frequented by foreigners.

"This restaurant carries the repute that foreigners come here because hard drinks are served with food. The fact that militants chose to strike the place on a weekend night shows that they had done their homework," a senior security official involved in the investigation told AFP.

Officials suppose that the bomb was either planted in the restaurant’s garden or thrown over a wall. The blast was heard in Islamabad at about 8.45 p.m.

According to the New York Times, Shahid Nadeem Baloch, the inspector general of the Islamabad police, said five Americans were among the wounded people.

As U.S. and British embassy personnel were also injured, embassies are on alert, reviewing their security practices and warning their employees to be cautious.

A notice placed on the embassy’s website on Saturday asked Americans not to go in places where Westerners are known to meet.

"American citizens should stay alert, be aware of their surroundings, reduce travel to a minimum, and act self-defensively," the notice said.

The Foreign Ministry said Sunday that the Turkish woman who was killed in the explosion was a foreign aid group worker.

There was a series of attacks in Pakistan since the parliamentary elections on February 18.

The explosion on Sunday came four days after two suicide bombings that killed 27 people in the city of Lahore.