Elderly US development worker Warren Weinstein has appeared in an Al-Qaeda video for the first time since he was kidnapped inPakistan just days before he meant to return home last August.

The two minute, 40 second video was posted on jihadist forums by Al-Qaeda's media arm as-Sahab on Sunday, according to the US monitoring service SITE. There is no indication of when the video was made and Weinstein appears alone before the camera.

Dressed in a traditional Pakistani tunic and speaking impassively in English, he urges US President Barack Obama to respond to his kidnappers' demands.

He also tells his wife Elaine that "I'm fine, I'm well, I'm getting all my medications, I'm being taken care of".

There was no response from the US embassy in Islamabad. Pakistani security officials said they were not immediately aware of the video but believe Weinstein is being held by Al-Qaeda and local Talibannear the Afghan border.

Weinstein, who turns 71 this year, suffers from asthma, heart problems and high blood pressure.

"If you accept the demands, I live; if you don't accept the demands, then I die," Weinstein told Obama in the video, sitting behind a table with books and food on it.

Al-Qaeda leader Ayman al-Zawahiri in December claimed that the group was holding Weinstein, but at the time provided no proof.

Zawahiri demanded that Washington end air strikes in Afghanistan, Pakistan, Somalia and Yemen, and release the 1993 World Trade Centre bombers along with relatives of Osama bin Laden.

Pakistan last month deported bin Laden's widows and children to Saudi Arabia, a year after they were detained following the US commando operation that found and killed the Al-Qaeda founder in Abbottabad.

Weinstein was snatched after gunmen tricked their way into his Lahore home on August 13, just days before he was due to return to the United States after seven years in Pakistan.

He was country director for US-based consultancy J.E. Austin Associates, which does contracting work with the US government's development agency, USAID.

Pakistani security officials believe Weinstein is being held in Pakistan's lawless northwestern tribal belt, probably close to North Waziristan, which is the focus of US drone strikes targeting Al-Qaeda and the Taliban.

Informants have suggested he is moved regularly to avoid detection.

"He is with Al-Qaeda and local Taliban, but we are unaware about his exact location," one security official told AFP on condition of anonymity.

Weinstein's kidnapping started a wave of abductions of foreign aid workers in Pakistan.

On April 29, British aid worker Khalil Dale was found beheaded in the southwestern city of Quetta, with a note from his captors saying he had been killed because their demands were not met.

He was snatched on January 5. Three other foreign aid and development workers remain in captivity: a German, an Italian and a Kenyan.

A Swiss couple snatched in southwest Pakistan in July last year were held for nine months before claiming to have escaped in March, but the nature of their liberation is clouded in mystery.