Article published on the 2008-06-06 Latest update 2008-06-06 15:17 TU
The government says that charities will only be allowed to resume operations if the pledge not to interfere in politics.
"They were involved in political activities and behaving like political parties when they were supposed to complement government efforts," Deputy Information Minister Bright Matonga told the AFP news agency.
He invited them to "clearly state what they intend to do, so that they will be bound by that".
Aid groups, which provide staple foods to much of the population, were earlier told to channel their efforts through local officials and the largest, Care International, was recently ordered to suspend operations.
The UN Security Council has expressed concern over the detention of the diplomats on Wednesday.
US ambassador to Zimbabwe James McGee said that a convoy, including his own, of three vehicles was stopped at a roadblock on Wednesday and then sped away.
One car was then forced off the road and its tyres slashed, while liberation war veterans threatened to burn its occupants, he added.
"It has to be considered the most serious of incidents when diplomats have guns pulled on them by the police of a country, when they’re surrounded, when they’re threatened with being burnt alive," US Assistant Secretary of State for African Affairs Jendayi Frazer told RFI in South Africa. "This just shows what the Zimbabwean people themselves are actually experiencing."
Police said that the diplomats had been attending a meeting with an opposition activist and behaved like "common criminals" by driving off when stopped by police.