WASHINGTON - The Trump administration has decided to halt the CIA's covert programme to equip and train certain rebel groups fighting the government of Syrian President Bashar al-Assad, two US officials said, a move sought by Assad ally Russia.

The US decision, said one of the officials, is part of an effort by the administration to improve relations with Russia, which along with Iranian-supported groups has largely succeeded in preserving Assad's government in the six-year-civil war.

The CIA programme began in 2013 as part of efforts by the administration of then-President Barack Obama to overthrow Assad, but produced little success, said the officials, both of whom are familiar with the programme and spoke on the condition of anonymity.

The Washington Post was first to report the programme's suspension on Wednesday. White House spokeswoman Sarah Sanders declined to comment on the topic at the White House briefing. The CIA also declined to comment.

The decision was made with National Security Adviser H.R. McMaster and CIA Director Mike Pompeo after they consulted with lower ranking officials and before Trump's July 7 meeting with Russian President Vladimir Putin at the G-20 summit in Germany. It was not part of US-Russian negotiations on a ceasefire in southwestern Syria, the two officials said.

One of the officials said the United States was not making a major concession, given Assad's grip on power, although not on all of Syria, "but it's a signal to Putin that the administration wants to improve ties to Russia."

Trump is under intense scrutiny by Congress and a special counsel investigating Russian interference in the 2016 presidential election and whether Trump's campaign had ties to the activity. Russia has denied US intelligence agencies' allegations of Moscow meddling, and Trump has denied collusion between his campaign and Russians.

A downside of the CIA programme, one of the officials said, is that some armed and trained rebels defected to Islamic State and other radical groups, and some members of the previous administration favoured abandoning the programme.

Before assuming office in January, Trump suggested he could end support for Free Syrian Army groups and give priority to the fight against Islamic State.

A separate effort by the US military effort to train, arm and support other Syrian rebel groups with air strikes and other actions will continue, the officials said.

However, aside from air strikes after the Syrian military launched a chemical weapons attack, the Trump administration has not increased military support from the limits set by the Obama administration.

IS falling ‘very fast’:

Trump at Pentagon

The Islamic State group is falling “very fast,” US President Donald Trump said Thursday as he visited the Pentagon for a military strategy meeting.

“We’re doing very well against ISIS. ISIS is falling fast, very fast,” Trump said, using another acronym for IS. Trump’s comments come at the six-month mark of his presidency, for which he campaigned by vowing to quickly defeat IS.

While the strategy to beat the jihadists in Iraq and Syria follows largely that of the Obama administration, Trump has given battlefield commanders more power to call in strikes and make real-time decisions.

IS has suffered a string of setbacks over the past two years, including the loss of their Iraq bastion Mosul earlier this month.

The intense destruction of the city and ongoing operations to retake Raqa in Syria have led critics to say the Trump administration is paying less attention to protecting civilians.

Rebel ambush kills 28 regime fighters near Damascus

At least 28 Syrian government soldiers and pro-regime fighters were killed Wednesday in a rebel ambush in the Eastern Ghouta region near Damascus, a monitor said Thursday.

The fighters came under attack by the Army of Islam rebel group as they attempted to advance in the town of Al-Rihan, the Britain-based Syrian Observatory for Human Rights said.

The Eastern Ghouta region is a major rebel stronghold near the capital, and it has been the frequent target of government military operations.

Observatory director Rami Abdel Rahman said rebels opened fire on the government troops as they entered an area where the opposition fighters had planted mines.

He said the ambush was the deadliest incident for government fighters in Eastern Ghouta since February 2016, when 76 regime troops were killed in Tal Sawane.

Eastern Ghouta is in one of the four proposed "de-escalation zones" designated in an agreement reached by government allies Iran and Russia and rebel backer Turkey in May. But the deal has yet to be fully implemented over disagreements on the monitoring mechanism for the safe zones.

In recent weeks, government warplanes have bombed the Ain Terma area that links Eastern Ghouta to the rebel-held parts of the Damascus neighbourhood of Jobar.

More than 330,000 people have been killed in Syria since its conflict broke out in March 2011 with anti-government protests.