Under a deal reached last year and backed by the Security Council, President Joseph Kabila was allowed to remain in office beyond his term until elections in late 2017.
But concerns are growing that the deal is collapsing after the head of the electoral commission said last week that the vote will likely not be held this year.
"Election delays cannot continue," US Deputy Ambassador Michele Sison told the council during a meeting on the crisis in the mineral-rich African country.
The deputy ambassador demanded that the commission "immediately" publish an electoral calendar and specifically set a date for the presidential election to put in motion the DR Congo's first democratic transition.
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The United States and the European Union have imposed sanctions on several officials close to Kabila over the election delays and human rights abuses, in particular in the Kasai region.
"We are ready to take additional action to sanction those who stand in the way of the DRC's first democratic transition of power," said Sison.
France and Britain also demanded that a date for the presidential vote be announced and stressed that there was no alternative to the New Year's Eve agreement on ending the political crisis.
UN peacekeeping chief Jean-Pierre Lacroix told the council that worsening violence had led to a sharp increase of 26 per cent in the number of displaced people over the past two months to reach 1.3 million.
A UN commission of inquiry has been established to investigate the killings in the Kasai while a separate UN panel is preparing to release this month the findings of its probe of the murder of two UN experts.
The bodies of American Michael Sharp and Swedish-Chilean Zaid Catalan were found in March, weeks after they had disappeared while investigating reports of mass graves in the Kasai.