Thousands of Vietnamese soldiers left Cambodia as part of Hanoi’s biggest withdrawal of troops in 10 years of fighting. Officials said that in all, 18,000 soldiers from six army divisions will return to Vietnam by river and road over the next few days. Some of the troops said as they crossed the border that they had served one to 10 years of duty in Cambodia, but they appeared reluctant to talk in the presence of officers. A Vietnamese army spokesman said last week that by the end of the year, 50,000 soldiers will have left Cambodia. A remaining 50,000--one-quarter of the invasion force Hanoi sent to Cambodia 10 years ago to topple the Khmer Rouge--will be home by 1990, the Vietnamese government says.