It's rather premature to be speculating about U.S. involvement in this matter, when there is zero evidence to support that claim, and plenty of reasons for this to happen internally in Iran.
It is premature to speculate of the US involvement, but this involvement is very probable.
Nicked it off another forum
http://www.ciponline.org/asia/reports/pakistan_the_state_of_the_union.pdf
The Pakistanis also suspect Iran of supporting Baluch activists in order to counter a
Pakistan-U.S. plot to make Baluchistan a rear base in a future offensive against Tehran.29 Iran, which
is keen on becoming the preferred outlet to the sea for Central Asia at Pakistan’s expense, has built
its own port at Chah Bahar (recently renamed Bandar Beheshti) with Indian assistance.30
Iranian involvement is unlikely. Tehran has denied any involvement in the troubles in
Baluchistan, claiming that it is not hostile to the Gwadar project.31 If it were to get involved in the
Baluch imbroglio, it would probably not be in opposition to Pakistan and certainly not because of its
rivalry with Pakistan over providing an outlet to the sea for Central Asia. Iran and Pakistan have a
common interest in exporting Iranian gas to India, and an insurrection in Baluchistan would only
harm their chances of building a gas pipeline through the province.32 Iran also has reason to worry
about Baluchistan’s claims to its border regions. In fact, Tehran sent helicopters to Islamabad
between 1973 and 1977 to help it put down the Baluch insurrection.
Finally, the Baluch as well as the Pakistanis see the United States as a potential
troublemaker. Some Pakistanis suspect that Washington would like to use Baluchistan as a rear
base for an attack on Iran and would also like to get China out of the region.33 They do not make
clear which side the Americans are on: whether they are opposing the Baluch nationalists because
they are supported by Iran or whether they are supporting the Baluch because they are hostile to the
Chinese. Other Pakistanis see a continuation of the “Great Power game” being played in Central Asia
since the collapse of the Soviet Union. Proponents of this view believe that the United States, in
competition with China and Iran, would like to control the oil supply lines from the Middle East and
Central Asia and would also like to use its Greater Middle East initiative to dismantle the major
Muslim states and redefine borders in the region.34 In contrast, some Baluch nationalists charge the
United States with conspiring with the Pakistan government to put an end to Baluch claims.
So far nobody has been able to prove any of these accusations.