Pakistan's military is warning of “grievous consequences” for the country, following the prime minister's remarks that army and intelligence chiefs acted unconstitutionally.

The military said Wednesday the remarks by Prime Minister Yousuf Raza Gilani have “very serious ramifications,” after he said this week that two top security officials acted unlawfully by making unilateral submissions to an ongoing Supreme Court inquiry.

Mr. Gilani also told China's People's Daily online that army chief General Pervez Ashfaq Kayani and Inter-Services Intelligence head Lieutenant General Ahmad Shuja Pasha should have sought government approval before submitting statements to the Supreme Court.

The court is investigating a controversial unsigned memo that allegedly sought U.S. help in preventing a military coup in Pakistan.

On Wednesday, Mr. Gilani fired Defense Secretary Naeem Khalid Lodhi, who is a retired lieutenant general, for “gross misconduct” and “illegal action” related to his role in submitting the army and intelligence chief's statements to the Supreme Court.

Lodhi was replaced by a government official, Nargis Sethi.

Wednesday's developments highlight the growing tensions between Pakistan's civilian government and the military.

A Supreme Court-appointed panel is investigating the origins of an unsigned memo in which Pakistan's civilian government asked for U.S. help in reining in the Pakistani military, following the U.S. raid that killed Osama bin Laden last May.

The existence of the document came to light in October when Pakistani-American businessman Mansoor Ijaz accused the then-Pakistani Ambassador to the U.S., Husain Haqqani, of writing the memo. Haqqani denies he wrote the document and has since resigned.

U.S. military officials confirmed that the top U.S. military officer at the time, Admiral Mike Mullen, received the memo but did not find it credible.

Prime Minister Gilani made his remarks about army chief Kayani and ISI head Pasha while army Kayani was visiting China.