Patna, Jan 22 (IANS) The number of tigers in Bihar's Valmiki Tiger Reserve has increased from 22 to 28, an official said Thursday.

"The National Tiger Conservation Authority (NTCA) has confirmed that the number of tigers in the Valmiki Tiger Reserve in West Champaran district has reached 28, according to the latest report on tiger population in India," said Vivek Kumar Singh, forest official.

NTCA conducted a census in all 44 tiger reserves in the country after a gap of four years to assess their status.

"A team of experts visited the Valmiki Tiger Reserve last year to collect samples like pugmarks and excreta of tigers. The NTCA conducted DNA tests to verify the number of tigers," another forest official R.B. Singh said.

According to a census conducted through the camera trap method by the World Wildlife Fund, there were 22 tigers in the Valmiki Tiger Reserve in 2013.

The reserve covers an area of 899.38 sq km which is 17.4 percent of the total geographical area of West Champaran.