Indian Prime Minister Narendra Modi will not attend a regional summit of South Asian leaders in Pakistan in November because of increasing cross-border attacks in the region, the foreign ministry said on Tuesday.

India blames Pakistan for a deadly assault on an army base in the disputed region of Kashmir this month that has escalated tensions between the rivals.

India says a group of militants crossed the de facto border that separates the countries and killed 18 soldiers on September 18, the biggest loss of life for Indian security forces in the region for 14 years.

Pakistan rejects the accusation and says India needs to conduct a proper investigation before it apportions blame.

Modi was scheduled to attend the South Asian Association for Regional Cooperation (Saarc) summit in Islamabad, which brings together eight member states in the region.

"India has conveyed to current Saarc chair Nepal that increasing cross-border terrorist attacks in the region...have created an environment that is not conducive to the successful holding of the 19th Saarc summit," the foreign ministry said in a statement.

"In the prevailing circumstances, the Government of India is unable to participate in the proposed summit in Islamabad."

According to Indian media reports, Afghanistan, Bangladesh and Bhutan too will not be attending the Summit.-Reuters