KINSHASA, Dec 13 (Reuters) - Democratic Republic of Congo President Felix Tshisekedi said on Monday he would ensure that the presence of Ugandan troops in Congo, where they are fighting an Islamist militant group alongside Congolese forces, was for a strictly limited period. Uganda and Congo launched a joint operation this month against the Allied Democratic Forces (ADF), an armed group allied with Islamic State, but have given few details about its scope or expected duration. read more "I will ensure that the presence of Ugandan troops on our soil is limited to the time strictly necessary for this operation," Tshisekedi said in a state of the union speechthat also covered the economy and COVID-19. Uganda"s intervention has provoked unease because of its army"s conduct during Congo"s 1998-2003 civil war, when Uganda was accused of occupying territory and plundering resources. read more At least 1,700 Ugandan soldiers have crossed into eastern Congo, and Uganda"s defence ministry has said its troops will stay as long as needed to defeat the ADF. read more On the economy, Tshisekedi said he had asked his government for additional reforms to boost revenue collection. Reforms have helped improve Congo"s economic outlook, with growth expected to reach 6.4% in 2022, the IMF said last week. read more "Despite this progress, too many in Congo are still struggling to make ends meet," Tshisekedi told parliament, listing shortcomings in infrastructure and basic services, to jeers from opposition MPs. Tshisekedi"s main rival, Martin Fayulu, had called for a sit-in at the electoral commission on Monday to demand the resignation of the organisation"s head, who is seen as close to the president. Police, however, blocked roads leading to the commission"s headquarters. Tshisekedi said preparations were underway to ensure timely, transparent elections in 2023 and he urged people to get vaccinated against COVID-19. Congo has the world"s lowest coronavirus vaccination rate, with roughly 0.1% of its 90 million population inoculated. "I have asked the government to accelerate the implementation of projects with rapid and visible impact," Tshisekedi said. The ministry of health on Monday announced the presence of the Omicron coronavirus variant in the country, as well as an exponential increase in cases of the disease, indicating the start of a fourth wave.