Pakistan President Asif Ali Zardari suffered a "minor heart attack" and is in Dubai for treatment but will return to Islamabad, a minister said. (Ishara S. Kodikara/AFP/Getty Images)

Pakistani President Asif Ali Zardari was in stable condition at a Dubai hospital Wednesday after medical tests relating to heart problems, the government said, dismissing rumors that the embattled leader was about to resign.

Zardari flew to the Persian Gulf city on Tuesday after “symptoms” related to a preexisting cardiac condition, the prime minister’s office said in a statement. Doctors were trying to determine whether the symptoms were a reaction to medication, the statement said.

A cabinet minister who spoke on the condition of anonymity said Zardari had suffered a minor heart attack but was “fine.”

Earlier, the government said Zardari was in Dubai only for a routine checkup. The trip, which comes amid a simmering “Memogate” controversy that has raised pressure on his administration, sparked speculation on Twitter and in one U.S. publication that Zardari would soon step down for health reasons or under pressure from the powerful Pakistani military.

The president’s spokesman, Farhatullah Babar, said Wednesday that such claims were “speculative, imaginary and untrue.” The prime minister’s office said Zardari would remain under observation for an unspecified period but would “resume his normal functions.”

Zardari was due to address Parliament in the coming days amid political intrigue surrounding the memo scandal, the latest threat to his wobbly and unpopular government. Tensions between Washington and Islamabad are soaring after a NATO airstrike late last month that killed 24 Pakistani soldiers, infuriating the Pakistani army and public, and Zardari was expected to discuss the incident in his address.

A senior Obama administration official said Wednesday that Pakistani officials had informed the United States that Zardari was undergoing medical treatment but would return to Pakistan to address Parliament within a few days.

The political scandal in Pakistan centers on an unsigned memo that solicited Washington’s help to rein in the Pakistani military and prevent a possible coup in the days after the U.S. raid to kill Osama bin Laden in May. The Pakistani American businessman who delivered the memo to Adm. Mike Mullen, then the chairman of the Joint Chiefs of Staff, said the memo was conceived by Pakistan’s then-ambassador to the United States with the backing of Zardari.

The ambassador, Husain Haqqani, denied involvement but resigned last month over the scandal. The memo is said to have outraged the Pakistani army, which largely controls the nation’s relationship with the United States and has little faith in the civilian government.

Pakistan’s state-run news agency reported that personal physicians and staff members accompanied Zardari to Dubai. Government officials did not say when he would return to Pakistan.

Zardari’s departure was enough to set a country with a history of military coups — and where no elected government has lasted a full term — swirling with rumors. One theory held that the army had urged Zardari to step aside and that he had elected to do so outside the country, perhaps to avoid prosecution over allegations of corruption.

The resignation conjecture gained traction after the Web site of Foreign Policy magazine quoted an unnamed former U.S. official as saying that Zardari might step down because of “ill health” exacerbated by the memo storm.

Members of Zardari’s Pakistan People’s Party said opposition politicians were fueling the rumors.

“This is another addition to the propaganda against the president,” said a party insider who spoke on the condition of anonymity.

“He was healthy and smoking a cigar when I was with him a few days back,” said Syed Akhunzada Chitan, a People’s Party lawmaker. “There is nothing to worry about.”

Hussain is a special correspondent. Special correspondent Haq Nawaz Khan in Peshawar, Pakistan, and staff writer Karen DeYoung in Brussels contributed to this report.