Sri Lanka's Sanjeeva Ranatunga, fielding at third man, was the target for the missiles - a piece of broken glass, a stone and an orange - and the umpires decided on an early tea after the authorities failed to quell the trouble.
Pakistan's total of 235 for 3 was built around half-centuries by their new captain Ramiz Raja (78), Saeed Anwar (50) and Inzamam-ul-Haq (68no). Ramiz departed just two balls before the close, which came early due to bad light, when a miscued pull gave an easy catch to mid-on.
In the County Championship it was a tale of a new captain and a departing one at Cardiff. Paul Johnson, next season's Nottinghamshire skipper, took over early from Tim Robinson and put Glamorgan in. Hugh Morris, who has announced his retirement from the Glamorgan captaincy, took full advantage with an unbeaten 144 to lead his side to 344 for 5. His fifth century of the season came off 165 balls with 16 fours.
He enjoyed a profitable partnership of 113 with Tony Cottey before Cottey was caught by Paul Pollard for 57 off Bates.
For the second successive day there was no play at Southampton, Old Trafford and Scarborough.
Gloucestershire's Andrew Symonds will announce on Monday whether he has decided to be English, and take his place on the A Tour to Pakistan, or Australian.