BEIRUT – The Latest on the White House saying it has "potential" evidence that Syria's government is preparing another chemical weapons attack (all times local):
The Trump administration is warning that Syria will pay "a heavy price" if it follows through on what the U.S. says are preparations for another chemical weapons attack.
The administration is threatening a response that could plunge the U.S. deeper into a civil war alongside the fight against Islamic State militants.
President Donald Trump has said he won't stand for Syria's use of chemical weapons.
The Pentagon says it had detected "active preparations" by Syria for a chemical attack.
The Syrian government, which has denied that it ever used banned chemicals, is rejecting the latest U.S. allegation. And Syrian allies Russia and Iran are accusing the United States of escalating tensions.
Syrian rebels say they do not rule out the possibility of another chemical weapons attack by President Bashar Assad's government — even after punitive U.S. missile strikes after the attack in April.
Jamil Saleh, the commander of the rebel Jaysh al-Ezzah faction, on Tuesday called for renewed airstrikes on the Shayrat Air Base in central Syria, where the United States alleges the government is preparing another chemical attack.
The U.S. struck the base in April after a gas attack killed 89 people in the rebel-held town of Khan Sheikhoun in northwestern Syria. The U.S. says that attack was launched from the Shayrat air base. It was the second nerve gas attack the U.S. has attributed to the Syrian government since 2013.
Saleh says "there are a million reasons for striking Assad."
Mohamad Abo Zayd, spokesman for the Turkish-backed rebel Ahrar al-Sham faction, says his group had no indication the government was preparing another attack, but that it doesn't "rule anything out."
Syrian military media has published a video of President Bashar Assad inspecting the Russian Hmeimim air base in western Syria and climbing into the cockpit of a Russian SU-35 fighter jet.
The military media outlet says Assad was accompanied by the Russian Army's Chief of Staff, Gen. Valery Gerasimov, to inspect the base near the coastal city of Latakia.
Russia's air intervention from September 2015 against rebels pushed the Syrian civil war decisively in Assad's favor.
Photos posted by the military media showed a Russian helicopter and armored trucks on base.
The president wore a business suit and was accompanied by Russian staff in military uniform.
Iran's foreign minister has denounced as a "dangerous escalation" the White House allegations that Syria is preparing a new chemical weapons attack.
Mohammad Javad Zarif wrote on his twitter account on Tuesday that the warning is based on a "fake pretext" and added that it "will only serve ISIS, precisely when it's being wiped out by Iraqi & Syrian people."
ISIS is an alternative acronym for the Islamic State group.
Zarif's remarks follow Monday's White House warning that Syrian President Bashar Assad and his military would "pay a heavy price" if they go ahead with the attack.
Iran is Assad's key regional backer in his fight against his opponents since the Syrian crisis began in 2011.
The Pentagon says the U.S. has seen chemical weapons activity at a Syrian air base that was used for an April sarin gas attack.
Capt. Jeff Davis, a Pentagon spokesman, said Tuesday the activity at the Shayrat air base indicates "active preparations for chemical weapons use."
The U.S. accused Syrian forces of launching a chemical attack from the base in April that killed dozens of civilians. In response, President Donald Trump ordered the military to fire about 60 cruise missiles at the base.
The White House warned late Monday that Syrian President Bashar Assad and his military would pay a "heavy price" for another chemical weapons attack. Assad's government and his allies deny the allegation.
The U.S. military says it will assess allegations that a coalition airstrike may have killed over 40 prisoners held in an Islamic State-run jail in eastern Syria.
Central Command confirmed to the AP on Tuesday that it struck IS facilities in the town of al-Mayadeen in the province of Deir El-Zour the day before.
Syrian activists reported an IS jail was struck in the area on Monday, and said at least 42 prisoners were killed, along with several IS fighters.
CENTCOM said it would publish the results of its assessment in its monthly civilian casualty report.
It said the Mayadeen mission was "meticulously planned and executed to reduce the risk... to non-combatants."
The Kremlin is dismissing the White House's warning that the Syrian government is preparing a new chemical attack and that President Bashar Assad and his military "will pay a heavy price" if it goes ahead.
Russian President Vladimir Putin's spokesman Dmitry Peskov says that "such threats to Syria's legitimate leaders are unacceptable."
Russia is Assad's key backer and sided with him when he denied responsibility for a chemical weapons attack that killed dozens of people in Idlib province on April 4.
Days later, President Donald Trump ordered a retaliatory cruise missile strike on a Syrian government-controlled air base.
Peskov criticized the Trump administration for using the phrase "another chemical weapons attack," arguing that an independent investigation into the April attack was never conducted despite Russia's calls for one.
Syrian activists say an airstrike targeting an Islamic State-run jail in eastern Syria has killed at least 42 prisoners.
The Britain-based Syrian Observatory for Human Rights says at least 15 IS jailers and fighters were also killed in the airstrike that happened on Monday in the Deir El-Zour province.
The activist-run Deir Ezzor 24 media outlet says at least 60 civilians were killed. It says the building belonged to an al-Qaida-linked commander before it was seized by the IS group in 2014.
The two groups said the U.S.-led coalition was behind the strike. It was not clear how they identified the aircraft responsible. The coalition could not immediately be reached for comment.
In addition to the coalition, Russia and Syria often carry out airstrikes against IS in eastern Syria.
A Syrian minister has dismissed a White House statement alleging that President Bashar Assad's government is preparing a new chemical weapons attack, saying Damascus has not and will not use such arms.
Ali Haidar, the minister for national reconciliation, told The Associated Press on Tuesday that the White House statement foreshadowed a "diplomatic battle" that would be waged against Syria in the halls of the U.N.
The U.S. holds Assad's government responsible for two sarin gas attacks that together killed hundreds of civilians in 2013 and earlier this year.
The White House statement on Monday night was made without forewarning and caught State Department officials by surprise.
The White House has issued a stern warning to Syrian President Bashar Assad, claiming "potential" evidence that Syria was preparing for another chemical weapons attack.
In an ominous statement issued late Monday with no supporting evidence or further explanation, Press Secretary Sean Spicer said the U.S. had "identified potential preparations for another chemical weapons attack by the Assad regime that would likely result in the mass murder of civilians, including innocent children."
He said the activities were similar to preparations taken before an April 2017 attack that killed dozens of men, women and children, and warned that if "Mr. Assad conducts another mass murder attack using chemical weapons, he and his military will pay a heavy price."
The White House offered no details on what prompted the warning.