A Chinese telecommunications equipment company has sold Iran's largest telecom firm a powerful surveillance system capable of monitoring landline, mobile and internet communications, interviews and contract documents show. The system was part of a...contract for networking equipment supplied by...ZTE Corp to the Telecommunication Co of Iran...Human rights groups say they have documented numerous cases in which the Iranian government tracked down and arrested critics by monitoring their telephone calls or internet activities...ZTE's..."Packing List,"...includes hardware and software products from some of America's best-known tech companies, including Microsoft Corp, Hewlett-Packard Co, Oracle Corp, Cisco Systems Inc, Dell Inc, Juniper Networks Inc and Symantec Corp. ZTE has partnerships with some of the U.S. firms. In interviews, all of the companies said they had no knowledge of the TCI deal. Several - including HP, Dell, Cisco and Juniper - said in statements they were launching internal investigations after learning about the contract...Li Erjian, a ZTE spokesman in China, said his company only sells "standard" equipment to Iran.