"I am continuing for one year the national emergency declared with respect to certain actions of the government of Syria," President Obama said in two documents signed by him on May 7 and released by the White House on Friday.
The measures "to deal with that emergency must continue in effect beyond" May 11, he said.
Bush, declaring a national emergency on May 11, 2004, imposed economic sanctions on Syria over charges that it was a state sponsor of terrorism. They were extended in 2006 and then tightened the following year.
Bush again renewed the sanctions for one year in May last year, banning exports of products other than food and medicine and freezing a raft of Syrian assets.
The Obama documents accused Syria of still "supporting terrorism, pursuing weapons of mass destruction and missile programs, and undermining (costly) US and international efforts" to stabilize and rebuild Iraq.
For these reasons, it added, "Syria continues to pose an unusual and extraordinary threat to the national security, foreign policy, and economy of the United States."
State Department spokesman Robert Wood told reporters that Obama's order "shows you that we still have some very serious concerns about Syrian behavior and activity in the world."
Ties between Washington and Damascus strained after the US-led invasion of Iraq in 2003, and the assassination of Lebanese leader Rafiq Hariri in 2005 which was blamed on Syria.
Washington recalled its ambassador in February 2005 following Hariri's murder and no decision has yet been taken on his replacement.
Damascus has denied any involvement in Hariri's killing, but withdrew its troops from Lebanon two months later, ending almost three decades of domination.
The United States accuses Syria and its non-Arab ally Iran of giving material support to the radical Palestinian movement Hamas and Lebanon's Hezbollah in their conflicts with Israel.
It also charges that Syria has turned a blind eye to Islamist militants entering Iraq through its border.
"We're willing to engage them in a dialogue to try to address not only our concerns but concerns that they may have," Wood said.
"But there's ... no secret we have some very serious problems with the government of Syria. And we hope to be able to try to work out those differences, but a lot of it is going to be up to Syria," he added.
The renewal of the sanctions comes as the United States is trying to engage diplomatically with Syria and as senior US officials Jeffrey Feltman and Daniel Shapiro returned to the country this week as part of those efforts.
In Damascus, Feltman said he held "constructive" talks on Thursday with Syrian Foreign Minister Walid Muallem.
"We noted in our discussions improvement in our ability to work bilaterally with the Syrians since our last visit here two months ago," said Feltman, the acting assistant secretary of state for Near Eastern Affairs.
Feltman and National Security Council Senior Director Daniel Shapiro are on their second visit to Damascus since Obama took office in January pledging to engage with all Middle Eastern countries, including Washington's foes such as Syria and Iran.
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