The Federation provided a key outlet for Tshombe to acquire mercenaries, smuggled weapons, and sell Katanga's minerals for cash. When the United Nations requested permission to post observers at the Katangese–Rhodesian border to halt the smuggling, Welensky refused to assent. Welensky heavily criticised UN peacekeeping operations in the Congo and the United Kingdom's response to the crisis. He used this as a means to mobilize white Rhodesian support for his government as it came under increasing pressure from the white supremacist Rhodesian Front (RF) party for failing to contain black nationalism within the federation. Welensky stayed in regular communication with Tshombe, though they did not not meet in person until late September 1961.