Uganda under Amin embarked on a large military build-up, which raised concerns in Kenya. Early in June 1975, Kenyan officials impounded a large convoy of Soviet-made arms "en route" to Uganda at the port of Mombasa. Tension between Uganda and Kenya reached its climax in February 1976, when Amin announced that he would investigate the possibility that parts of southern Sudan and western and central Kenya, up to within of Nairobi, were historically a part of colonial Uganda. The Kenyan Government responded with a stern statement that Kenya would not part with "a single inch of territory". Amin backed down after the Kenyan army deployed troops and armoured personnel carriers along the Kenya–Uganda border. Amin's relations with Rwanda were tense, and during his tenure he repeatedly jeopardized its economy by denying its commercial vehicles transit to the Kenyan port of Mombasa and made multiple threats to bomb Kigali.