The Director General of the ASI, Pravin Srivastava, said the digging area is now planned to be widened but clarified that the excavation work by his 12-member team has not been stopped.
The excavation work at the fort of Raja Rao Ram Bux Singh in the Daudia Khera village has reached a depth of 4.8 metres and yielded only pottery and artefacts supposed to be dating back to first century BC, he said.
"The Archaeological excavation is restricted between the space of two parallel brick wall and continued upto the depth of 4.80 metres below the surface. It has reached a level of kankar (gravel) formation in part of the trench which actually started from 4.60 metres," Mr Srivastava told reporters.
He said a team of Geological Survey of India with the consultation of the ASI officials at the site has suggested another area at the site close to river Ganga for trial excavation.
"Accordingly, a new trench XA2 has also been laid-out with proper cleaning of the surface and the digging would take place from tomorrow," he said.
The antiquities that have been recovered so far from this trench includes glass bangles, iron nails, hopscotch (game) and fragmentary miniature stone figure of lion.
Archaeologists began digging at the fort in Unnao nearly two weeks ago after a sage, Shobhan Sarkar, told a government minister about his dream of a 1,000-tonne gold treasure.
The ASI has denied that the excavation was linked to the sage's dream and said its search is based on the findings of the Geological Survey of India (GSI) that suggested gold or silver could be buried there.