Islamabad, Pakistan (CNN) -- Four militants armed with guns and grenades stormed a mosque in Rawalpindi frequented by military personnel, killing dozens of people Friday -- most of them children, the military said.
The attack is the latest to shake the garrison city since this year's launch of strong military offensives against Taliban insurgents in the Swat Valley and South Waziristan. Rawalpindi is the headquarters of the Pakistani army.
Maj. Gen. Athar Abbas said Friday's assault killed 36 people and wounded 75.
Among the dead were 17 children, according to the military's Web site. Also killed were an army general and eight other military officials, six of them of senior rank. The remaining fatalities were adults.
"As soon as the mosque's security staff checked me, there was a blast and then a finger hit me, then there was another," Ishtiaq, a driver for a military officer, told GEO TV.
Ishtiaq, who uses only one name, was attending midday prayers.
Rawalpindi is near Islamabad, and the mosque is near national army headquarters. It is located inside a walled residential compound where many military families have homes.
A witness told GEO TV there were up to 300 worshippers at the mosque at the time of the attack.
The militants hurled grenades before opening fire, Rawalpindi Police Chief Aslam Tareen told CNN. He said all the militants died, but he doesn't know how.
"These are not militants," Abbas said. "These are terrorists who killed innocent worshippers."
Retired Gen. Muhammad Yousaf was killed in the attack, said Col. Baseer Haider, a military spokesman. He said Yousaf was a former vice chief of army staff who was second in command during the administration of President Pervez Musharraf.
Abbas said two of the attackers were suicide bombers who blew themselves up inside the Parade Lane mosque; the other two were shot and killed by security forces outside the mosque.
Several explosions were heard inside the mosque around 1:30 p.m. (3:30 a.m. ET), followed by gunfire, Abbas said. The militants entered the compound by climbing over a wall, Tareen said.
This is the first attack in Rawalpindi since a suicide bomber targeted a bank on November 2.
On October 10, militants stormed army headquarters in Rawalpindi, taking several people hostage before security forces killed them.

In a highly tragic incident 36 innocent people including 17 children, 10 civilian, 9 Army personnel embraced shahadat when terrorists attacked a mosque in Parade Lane, Rawalpindi, Saddar today.
Reportedly 4 terrorists approached a mosque inside officers residential colony in Parade Lane, Rawalpindi Saddar and hurled grenades on Namazies followed by indiscriminate firing.

Meanwhile two suicide bombers entered the Mosque and blew themselves killing 35 Namazies who were offering Jumma prayers. Security forces personnel in the area responded immediately and 2 other terrorists were killed in exchange of fire.
75 personnel were injured in the same incident. Names of those who embraced shahadat are as under:-
S/No Rank Name
1. Major General Umer Bilal
2. Brigadier Abdul Rauf
3. Lieutenant Colonel Fakhar
4. Lieutenant Colonel Manzoor Saeed
5. Major Zahid
6. Major (Retd) Shoaib
7. Naik Masood
8. Sepoy Abdul Qayyum
9. Sepoy Sarwar
10. Child Bilal Riaz S/O Major General Nasim Riaz
11. Child Ali Hassan S/O Colonel Shabbir
12. Child Hassan S/O Colonel Shukhran
13. Child Sadaul Hassan S/O Lieutenant Colonel Fakhar
14. Child Zamin S/O Engineer Akmal Hussain
15. Child Qaisar Khan S/O Syed Akbar
16. Child Adil Rauf S/O Abdul Raud
17. Child Muhammad Khan S/O Sultan Bakhsh
18. Child Fazal Khan S/O Madad Khan
19. Child Hashim
20. Name not known S/O Brigadier ® Sadiq
21. Name not known S/O Brigadier Mumtaz
22. Name not known S/O Colonel Qaiser
23. Name not known S/O Colonel Kaleem Zubair
24. Name not known S/O Lieutenant Colonel Shoaib
25. Name not known S/O Major Saleem
26. Name not known S/O Major Ahsan
27. Deputy Director NLC Taskeen
28. F/O Major General Awais Mustafa
29. F/O Colonel Kaleem Zubair
30. F/O Lieutenant Colonel Farooq Awan
31. Civilian Kahlid Javed
32. Civilian Ghulam Mujtaba
33. Civilian Javed S/O Ghani Khan
34. Civilian Muhammad Fiaz
35. Civilian Asad
36. Civilian Name not known
SUMMARY
Ø Officers 06
Ø Soldiers 03
Ø Children 17
Ø Civilian 10