Beijing used disassociation from United States (US) policies pressuring Iran, along with elements of support for Iran in the face of US pressure, to gain access to Iranian energy resources. By giving the Islamic Republic of Iran (IRI) a degree of support against US pressure, Beijing encapsulated the Sino-Iranian energy relation in security cooperation that was meaningful to Tehran. Beijing carefully weighed the intensity of US demands along with probable injuries to both Sino-US and Sino-Iranian relations, and then acceded to or rejected particular US requests. Beijing's Persian Gulf dilemma intensified in the 2000s as US-led international concern over Iran's nuclear programs mounted. Growing hard-liner control over Iran's diplomacy during the second half of the 2000s further rendered Tehran's diplomacy more confrontational. A fact that influenced US policy and Beijing's calculation of the gains and losses associated with alignment with either Tehran or Washington.