A modified version of developer Sheldon Solow’s $4 billion mixed-use development project along the East River will come to a vote today and the City Council is poised to approve it, according to sources close to the negotiations.

Weeks of negotiations between local City Council Member Daniel Garodnick and Mr. Solow will culminate in a vote this morning by the council’s Subcommittee on Zoning and Franchises, and then later in the day by the Subcommittee on Land Use.

Approval will pave the way for a plan that, before modifications, called for the construction of six soaring residential glass towers with about 4,000 apartments, an office tower, and more than 500 public parking spaces just south of the United Nations.

It is unclear what concessions were made by Mr. Solow in recent days. Mr. Garodnick and Community Board 6 had previously objected to the heights of the proposed towers and the inclusion of a large commercial building in the complex.

A “yes” vote by the two subcommittees would most likely propel the project to final approval by the full 51-member council.

A vote scheduled to take place yesterday was canceled to allow more time for two sides to negotiate, and sources stressed yesterday evening that while an agreement was in place, there was still a chance that the deal could fall apart.

The Council must vote on the project tomorrow if it is to be approved. If not, it would take at least three months, and most likely far more, to gain approval through the city’s uniform land use approval process.

Last week, Mr. Solow floated the possibility of housing the U.N. offices at the planned 47-story office tower.

His spokesman, Michael Gross, declined comment.