LONDON: A BBC report quoted Afghan insurgent leader Siraj Haqqani on Monday as saying he's been approached by the United States to join the Afghan government and denying that his militant group was behind the killing of the top Afghan peace envoy.

The Pakistan-based Haqqani network is affiliated with both the Taliban and al-Qaida and has been described US and other Western nations as the top security threat in Afghanistan. The group has been blamed for hundreds of attacks, including a 20-hour siege of the US Embassy and Nato headquarters last month.

The group is led by Jalaludin Haqqani, but the ailing leader has relinquished most operational control to one of his sons, Siraj.

Last week, US officials accused Pakistan's spy agency of supporting the Haqqanis in attacks on Western targets in Afghanistan, the most serious allegation yet of Pakistani duplicity in the 10-year war.

The United States and other members of the international community have in the past blamed Pakistan for allowing the Taliban, and the Haqqanis in particular, to retain safe havens in the country's tribal areas along the Afghan border, particularly in North Waziristan.

The outgoing chairman of the US Joint Chiefs of Staff, Adm. Mike Mullen, has also claimed that Pakistan's military spy agency helped the group.

However, Haqqani told the BBC Pashtu service that while the group had contacts with a number of spy agencies, including that of Pakistan, during the Soviet invasion, there are now ''no such links that could be beneficial.''

''Right from the first day of American arrival till this day not only Pakistani but other Islamic and other non-Islamic countries including America, contacted us and they (are) still doing so. They are asking us to leave the ranks of Islamic Emirates,'' he said referring to the Taliban leadership.

He said that the outsiders have promised an ''important role in the government of Afghanistan,'' as well as negotiations.

Haqqani also denied that his group took part in the Sept. 20 assassination of former Afghan President Burhanuddin Rabbani. He headed the country's High Peace Council, set up by Afghan President Hamid Karzai to work toward a political solution to the decade-long war.

''We haven't killed Burhanuddin Rabbani and this has been said many times by the spokespersons of Islamic Emirate,'' he said.

Karzai's office has said a special commission investigating Rabbani's death had concluded the attack was planned in Quetta, the Pakistani city where key Taliban leaders are based. The delegation also said the primary assailant was a Pakistani citizen.

The BBC said it did not interview Siraj Haqqani directly. Working through an intermediary, the BBC drew a list of questions and received in return an audio file which it was able to verify as being him.