By Andrew MillsDOHA, June 30 (Reuters) - Top U.S. envoys were due to arrive in Qatar on Tuesday, but uncertainty over the timing and content of any diplomatic talks raised questions over efforts to bring a lasting halt to the Iran war and fully reopen the Strait of Hormuz.

Efforts to reopen the Strait without Iran’s oversight have sparked days of crossfire.

Tehran says no intention of holding meetings with US officials from 'technical teams' in Qatar this week.

Doha is set to host crucial talks between Iran and the U.S. this week, though Tehran denies any scheduled meetings with American officials. Weekend missile exchanges tested a…