Sources in western diplomatic circles told Blic.rs that the timescale of Vucic's visit to Washington, which was already slated for the coming year, was pushed forward due to US fears about Serbia's close ties and continued cooperation with Russia.
According to the paper, the call is a reflection of a recent statement from US Secretary of State John Kerry that Serbia is "in the line of fire" between the West and Russia.
"Visits by international leaders to Washington are usually planned around six months in advance," a diplomatic source told Blic, noting that the US ambassador to Serbia extended the invitation to Vucic on April 9. Biden's plan, however, "would see Vucic in Washington in May, or the beginning of June."
The formal invitation to Washington follows a verbal invitation Biden gave Vucic at last month's Munich Security Conference last month, when Biden also, according to local media, proposed the institution of a new gas deal with Serbia, via the construction of a terminal on the Croatian island of Krk, which the US administration says would be provided with gas by ships from the US, Algeria. or Qatar.
The proposal follows the obstruction late last year of the South Stream project, which aims to provide Serbia and other European countries with a secure supply of natural gas from Russia, using a pipeline running under the Black Sea to mainland Europe.