Analysts say the American vice-president and secretary of state are trying to prove loyalty without becoming political liabilities.

Vance lidera las encuestas para hacerse con la nominación presidencial republicana, aunque en los últimos meses Rubio ha recortado distancias

Trump has said that Rubio and Vance running together would make a "perfect ticket", but indicated that it was still way too soon to make a call between them.