Police in Pakistan say they still have no leads in the case of an American kidnapped from his home in the eastern city of Lahore.

Development expert Warren Weinstein was snatched by gunmen early Saturday after they overpowered guards and broke into his house.

Police officials said Tuesday that Weinstein's three security guards and driver were still being interrogated.

So far, the kidnappers have not contacted authorities or made any ransom demands.

The U.S. embassy in Pakistan says the U.S. Federal Bureau of Investigation is assisting Pakistani authorities to help locate Weinstein.

The 70-year-old U.S. citizen served as the director in Pakistan of a U.S.-based development consulting company, J.E. Austin Associates.

Weinstein had worked in Pakistan for more than five years and was scheduled to end his assignment and return to the United States this week.

Pakistani police say the kidnappers convinced Weinstein's guards to open a gate just before dawn Saturday, by offering to give them food. This type of generosity is common during the month of Ramadan, when people fast during daylight hours.

Kidnappings for ransom are fairly common in Pakistan, although foreigners are not usually targets.