By Jane Standley BBC New York Correspondent

New York state and city officials have speeded up the timetable for rebuilding the World Trade Center site, following criticism that the planning is moving far too slowly.

As the clean-up operation nears completion, the authorities have announced a new set of deadlines for rebuilding proposals to be submitted.

A master plan is now due to be in place by the end of the year.

Some relatives of victims want only a memorial on the site

A deadline of 1 July has been set for initial proposals to be submitted on how the site should be rebuilt.

The two agencies which will oversee the reconstruction - the Port Authority and the Lower Manhattan Development Corporation - must then whittle down the designs to a shortlist of three by 1 September.

It is a fast-paced schedule - companies which would like to submit proposals actually have only the next two weeks to apply to be in the running.

Difficult job

Rivalry and infighting between the two agencies responsible has hampered the drawing up of any serious timetable.

There is now hope that that has been resolved - but there are still difficulties to be considered by anyone wanting to put a plan forward.

Many relatives of the victims do not want anything built on the site, apart from a memorial.

Choosing a memorial will itself be a very difficult job.

There are few details concerning what the proposals for the site must contain - only that housing should not be included, and that no buildings should be more than 50 storeys high.