By Pam O'Toole BBC Middle East analyst

Washington's newly appointed envoy for "free Iraqis", Zalmay Khalilzad, has been holding his first meetings with Iraqi opposition groups in London.

Mr Khalilzad - whose appointment was announced on Monday - is expected to serve as Washington's focal point for co-ordination with the Iraqi opposition and to oversee preparations for a post-Saddam Hussein Iraq.

Dr Khalilzad will co-ordinate Iraqi opposition

His visit follows talks in London on Monday between Iraqi opposition groups and two senior US officials, Deputy Defence Secretary Paul Wolfowitz and Under-Secretary of State Marc Grossman.

The flurry of visits suggests that Washington is anxious to keep up its pressure on the Iraqi opposition to set aside its differences in the run-up to a major conference to be held in London next week.

Bickering continues

The main opposition parties had postponed convening the meeting for months, bogged down by disputes over how large it should be and who should be invited.

It was only after talks with a joint Pentagon-State Department team that the situation was finally resolved.

The opposition agreed to expand the number of delegates invited, and hold the conference on 13 December in London.

The guest list now includes more than 50 Iraqi opposition parties and organisations, and more than 100 independent Iraqi participants.

The organisers say they will also invite representatives of the five permanent members of the UN Security Council, along with representatives from countries neighbouring Iraq and from the European Union.

Among other things, the conference will consider a draft document called the Transition to Democracy in Iraq, drawn up by the main opposition parties and prominent independent intellectuals.

It is not clear how far the United States agrees with some of the proposals put forward in that document.

And, with only a week to go before the conference, low-level bickering appears to be continuing.

Some opposition groups and individuals are pressing for the guest list to be expanded still further.

And the main Shia opposition group boycotted talks with Mr Wolfowitz, in a dispute over Shia representation at that meeting.