In late June I noted that something seemed to have changed in Syria, that the threat to the Assad regime seemed more real than ever.

A massive explosion in Syria confirms that indeed things have changed.  The Syrian defense minister and a brother-in-law of Bashar Assad both were killed, via Jerusalem Post:

Syrian state television said a “terrorist explosion” which struck a national security building in Damascus killed Syrian Defense Minister Daoud Rajha and critically injured the country’s interior minister on Wednesday.

“The terrorist explosion which targeted the national security building in Damascus occurred during a meeting of ministers and a number of heads of (security) agencies,” the television.

Syrian General Hassan Turkmani, a former defense minister and senior military official, died of wounds sustained in the bomb attack, Hezbollah’s al-Manar television and a security source said.

A security force also told al-Manar that Assad’s brother-in-law Assef Shawkat was killed in the attack.

DEBKAfile reports:

Bashar Assad’s survival is in serious question after the deaths of his top allies, his brother-in-law Security Chief Assif Shawqat and Defense minister Gen. Dawoud Raijiha by a suicide bomber, while holding a top-level meeting in the National Security building in Damascus, Wednesday, July 18. Interior Minister Maj. Gen. Mohammad Ibrahim Shaair is in critical condition.

This was the deadliest blow to the Assad regime in the 17-month Syrian uprising, striking deep inside the president’s inner circle and family: Shawqat was married to his sister.  It took place on the fourth day of fierce fights with rebel forces which seized parts of Damascus and are battling superior government forces backed by heavy tank, artillery and machine gun fire and helicopters. The bomber must have had an inside track to the top level of the Assad regime to have come close enough to reach a cabinet meeting with security officials in the heavily fortified National Security building and blow himself up among them.

The Times of Israel reports that Syrian army cohesiveness is damaged:

An Israel Radio report said many Syrian troops deserted their positions in the capital after the blast. It quoted rebel sources saying troops had abandoned army vehicles and materiel as they fled.

Even the Russian foreign minister described the fighting as the decisive battle, via Reuters:

Russia said on Wednesday that a “decisive battle” was under way in Syria.

Foreign Minister Sergei Lavrov also warned that passing U.N. Security Council sanctions against Syria would amount to direct support for rebels and could draw the country into civil war.

“The battle for the capital, the decisive fight (is under way in Syria),” Lavrov told reporters in Moscow.

The big questions are what will Iran and Hezbollah do to save Assad and if he falls, and will Assad try to regionalize the conflict.