(REUTERS) -- Asif Ali Zardari returned to Pakistan on Friday from a trip to Dubai, his spokesman said, as speculation swirled over whether he would survive heightened tension between his civilian government and the country's powerful military.

Pakistan's

Pakistan's President Asif Ali Zardari is seen during a meeting in Istanbul November 1, 2011.

The president returned to Islamabad in the wee hours of Friday morning, the spokesman, Farhatullah Babar, told Reuters.

A disputed memo allegedly from Zardari's government seeking U.S. help in reining in the military has soured relations to their lowest point since a coup in 1999.

Military sources say that while they would like Zardari to go, it should be through constitutional means, not another of the coups that have marked half of Pakistan's almost 65 years of independence.