Troop withdrawal will not hit country's security: Afghan President Ashraf Ghani's chief adviser Fazel Fazly

Fazel Fazly, the chief adviser to the Afghan President Ashraf Ghani, tweeted: "The alarms raised about Afg's future in media were more rampant in Dec 2014. Most analysts believed that Afg would collapse with the departure of more than 100,000 troops. But our brave defense & security forces proved these analysts wrong & defended the nation with great valor."

"During the past four and half years, the fight on the frontline and security of the entire nation was carried out by the same forces, and despite the overwhelming war, our national armed and air forces have strengthened day by day and they will grow in strength even more," he said.

He further said: "If the few thousand foreign troops that advise, train & assist, leave it will not affect our security, in the past four & half years our security is completely in the hands of Afghans and the final goal is that ANDSF will stand on their feet to protect & defend soil on their own."

The US government is planning to reduce its troops posted in Afghanistan, media reports said on Friday.

The US military has been ordered to begin planning to withdraw about half the troops in Afghanistan, a US defence official with direct knowledge of the matter told CNN on Thursday.

The official told the US news channel that the planning is underway, and it could take months to withdraw the nearly 7,000 troops.

The decision has been taken at a time when the US also announced its move of withdrawing its military from Syria.

Several US defence officials told CNN that the country's President Donald Trump wants to draw down US troops in Afghanistan. 

James Mattis resigns:

Amid reports of differences with Trump over plans to withdraw troops from Syria, US Defense Secretary James Mattis resigned on Thursday, media reports said.

"Because you have the right to have a Secretary of Defense whose views are better aligned with yours on these and other subjects, I believe it is right for me to step down from my position," Mattis wrote in his letter to the President as reported by CNN.

A senior administration official told CNN that Mattis was "vehemently opposed" to the Syria decision and a possible Afghanistan troop withdrawal. 

Meanwhile, Trump tweeted that Mattis will retire at the end of February.

"General Jim Mattis will be retiring, with distinction, at the end of February, after having served my Administration as Secretary of Defense for the past two years. During Jim’s tenure, tremendous progress has been made, especially with respect to the purchase of new fighting," Trump tweeted.

The President did not name his successor.

"Equipment. General Mattis was a great help to me in getting allies and other countries to pay their share of military obligations. A new Secretary of Defense will be named shortly. I greatly thank Jim for his service!," he said.

Image: Ministry of Defence Afghanistan website