"It is crucial to our national interest to maintain a military and diplomatic presence in Syria", Tillerson said during his speech.
Billed as the Trump administration's new strategy on Syria, the announcement will prolong the risks and redefine the mission for the US military, which has for years sought to define its operations in Syria along more narrow lines of battling Islamic State and has about 2,000 USA ground forces in the country.
"(It's) not a bad system", he said, explaining that some early reactions to Trump's tweets have usually come in by the time he sees them. For this reason, we will seek to de-escalate the civil war in Syria, work for peace, and encourage all parties to head to the negotiating table.
The United States will maintain a military presence in Syria focused on ensuring the IS can not re-emerge, he said.
"Instead, we will encourage worldwide assistance to rebuild areas the global coalition and its local partners have liberated", Tillerson said, suggesting such an approach might pressure Assad to resign. And Republicans and Democrats in the USA have grown anxious that both of Assad's allies are now entrenched in the country, with Iran in particular posing an immediate threat to neighboring Israel.
Tillerson said the U.S. recognizes that Syria presents many complexities.
"The top US diplomat said Washington would carry out "stabilization initiatives" such as clearing landmines and restoring basic utilities in areas no longer under Islamic State control, while making clear that "'stabilization' is not a synonym for open-ended nation-building or a synonym for reconstruction.
"Assad's continued military operations against his own citizens... have created a humanitarian crisis of millions of refugees and only add to the instability in Syria", the Secretary said.
The Syrian government does not need one dollar from the United States for reconstruction because this dollar is stained with the blood of Syrians, the source said, adding that "the USA administration only creates destruction and suffering".
"We can not repeat the mistake of 2011", he said, alluding to President Obama's withdrawal of most USA combat troops from Iraq after nine years of war.
Tillerson also urged Russian Federation to play a "meaningful" role in handling the Syria issue.
The United Nations Special Envoy for Syria said on Wednesday he had invited the Syrian government and opposition to a special meeting next week in Vienna.
One of the starkest illustrations of the risks of the entanglement is unfolding now, as Turkey escalates threats to attack the Kurdish enclaves of Afrin and Manbij in northern Syria. The US has at least 2,000 troops in Syria, according to Pentagon figures released in December.
The source added that the United States presence and all what the U.S. administration has done are "aimed at protecting the Daesh (ISIL or ISIS) terrorist organization" which has been created by the USA administration, Syria's official news agency, SANA, reported.
The U.S.is also funding a Kurdish fighting force in Syria to combat ISIS, although U.S. ally Turkey considers those fighters terrorists.