"We reiterated our indisputable right to peaceful nuclear technology," he said at a joint press conference with his Syrian counterpart Walid al-Muallem.
The Iranian foreign minister also said that he would visit Kuwait on Saturday as part of regular consultations with Iran's Arab neighbours across the Gulf.
"I will tell them (Kuwaiti officials) that the Bushehr nuclear plant (under construction in southern Iran) is in keeping with the highest international norms and earthquake-resistant," he said.
"Kuwait lies some 120 kilometres (75 miles) away from the plant while our people live a kilometre away," said Mottaki.
He said on arrival from Jordan that his previously unannounced visit was prompted by "developments in the region which require talks" between Iran and its Syrian ally.
Turning to Iraq, Mottaki told reporters that both Syria and Iran, which opposed the US-led invasion of 2003, wanted "a timetable for the withdrawal of foreign troops".
As for a UN resolution passed on Wednesday that calls for Syria to establish full diplomatic ties with Lebanon, he said it amounted to "a violation of international law", although Tehran favoured better Beirut-Damascus ties.