Two top U.S. Defense Department officials have arrived here to begin talks centered on Iranian plans to slash proposed arms purchases, including a $1.2 billion aerial radar system, local newspapers reported yesterday.

Deputy Defense Secretary Charles Duncan and Pentagon arm sales director Lt. Gen. Ernest Graves reportedly met with Shah Mohammed Reza Pahlavi and other Iranian officials about the cutbacks, which are said to designed to save Iran $7 billion over the next five years.

In Washington, a State Department official said Iran has given American negotiators no indication that it wants to back out of the previously arranged arms purchases. Ghe official said the talks concern arms sales that have been negotiated but not formally concluded.

According to the newpaper accounts, however, Iran plans to cancel proposed purchases of the "Advanced Warning Airborne Control System" or AWACS, which was to be used on the Iranian-Soviet border to report Soviet military movement, 70 F-14 fighter-bombers, 140 F-16 fighters, 31 Phantom jets and 1,000 air-to-ground missiles.

The action is expected to ease the tense political situation in Iran, which has been rocked by antigovernment riots all year. An estimated 1,000 persons have been killed this year in the disturbances.

Yesterday police clashed with antigovernment protestors in two Iranian cities and at least 11 persons were killed or wounded, according to press reports reaching the capital.

In Gorgan, about 180 miles northeast of Tehran, 30,000 demonstrators tried to set fire to the headquarters building of the Iranian secret police, the reports said. Violence was also reported in Qum, 96 miles south of Tehran. Death tolls in each city were not immediately known. Meanwhile, mass demonstrations in Tehran and Mashad ended peacefully.