ISLAMABAD, April 20 (Reuters) - Pakistan has placed its first order for discounted Russian crude oil under a new deal struck between Islamabad and Moscow, the country's petroleum minister said, with one cargo to dock at Karachi port in May.

The deal will see Pakistan buy crude oil only, not refined oil, and imports are expected to reach 100,000 barrels per day if the first transaction goes through smoothly, Minister Musadik Malik told Reuters on Wednesday night.

"Our orders are in, we have placed that already," he said.

(Reporting by Asif Shahzad)