American abducted in Pakistan city of Lahore
An American citizen has been abducted by gunmen from his house in the Pakistani city of Lahore, police say.
The US embassy confirmed the abduction and named the man as Warren Weinstein.
Mr Weinstein has been in Pakistan for at least five years and has been working for the firm JE Austin on development in tribal areas. He was to return to the US on 15 August.
The abduction of Pakistanis for ransom is common and a few foreigners have been targeted by militant groups.
Police said about eight kidnappers attacked the house before dawn on Saturday.
One report said the Mr Weinstein's driver was forced to open the door, another that the security guards were tricked into opening the door by men with food offerings for the fasting month of Ramadan.
Mr Weinstein reportedly lived mainly in Islamabad but travelled to Lahore.
US embassy spokesman Alberto Rodriguez confirmed the abduction and said it was working with Pakistani authorities on the case.
No-one has yet said they carried out the kidnapping.
JE Austin Associates is a development contractor that works alongside the US government's aid arm.
Mr Weinstein is described on the firm's website as an "expert in international development with 25 years experience".
US-Pakistan ties have been strained since a US military raid into Pakistan killed al-Qaeda leader Osama Bin Laden in May.
And in February, many Pakistanis were angered when a CIA contractor, Raymond Davis, shot dead two men he said were trying to rob him in Lahore.
He was freed and sent home after the US paid compensation to the families of the dead.
Foreigners are infrequently targeted by kidnappers in Pakistan; the last such incident involved a Swiss couple who were kidnapped in the south-western province of Balochistan in July.
Five-year-old British boy Sahil Saeed was kidnapped when visiting his grandmother's home in the Punjab region on 4 March 2010.
He was released after being held for 12 days when a $180,000 (£110,000) ransom was paid by his family.