The U.N. Mission in Mali this week recognized the results of a Malian constitutional court declaring Keita, formerly the Malian prime minister, as president.
The spokesman for U.N. Secretary-General Ban Ki-moon said both leaders spoke by phone of the political processes in the country.
"The collective focus must now move to embedding democratic institutions, fostering national reconciliation and spearheading development through economic growth and job creation," U.N. special envoy to Mali Romano Prodi said in a statement Thursday.
The interim Malian government in January called for military support from former colonial power France to help tackle nomadic rebels and al-Qaida militants who seized control over northern Mali following a 2012 coup.
The BBC reported Algerian militant leader Mokhtar Belmokhtar announced his al-Qaida-linked group merged with its Malian counterparts to form a new terrorist movement, al-Murabitoun.
Belmokhtar was the ringleader of a January attack on a natural gas facility near In Amenas, Algeria, in which more than 800 people were taken hostage. At least 39 hostages and 29 militants were killed when Algerian special forces raided the site in attempt to free hostages.
Belmokhtar said the merger was in response to the French intervention in Mali.
Keita, during his presidential campaign, said the French intervention was a national embarrassment.