The Indian government on Wednesday barred Pakistani aircraft from its airspace until May 23 amid fears of open war between New Delhi and Islamabad.

The government issued the ban in a Notice to Airmen, according to Reuters. The move followed a terrorist attack in the disputed region of Kashmir that saw 26 people killed last week.

Pakistan's government has warned that an Indian attack is "imminent" and has reinforced its forces to prepare for such a move. The U.S. State Department, this week, confirmed it had reached out to both governments seeking to deescalate the situation.

The Kashmir region has been the subject of dispute since the 1947 partition of India and Pakistan and is mostly controlled by either party. China maintains a small stake in the territory.