The US government is concerned about the maintenance, let alone expansion, of its over US$3 billion bilateral trade with Pakistan after the latter's failure to introduce the Secure Freight Initiative (SFI) program at Karachi Port, the Business Recorder reported.

The local authorities, however, claim to have deep interest in the Pak-US joint venture, terming non-availability of the required 10-acre land as the only stumbling block in materialisation of the program.