"President Bashar al-Assad stressed more than once in (our) talks his firm intention to press ahead with the implementation of the Taif agreement and to plan a Syrian withdrawal from Lebanon in line with this agreement," he told reporters after meeting Assad in Damascus.
"The issue of Taif and the withdrawal is ... part of Syrian policy. There will be talk and steps that we will see soon," Moussa said.
The 1989 Taif agreement committed Syria to shifting its troops in Lebanon to the eastern Bekaa Valley. It also stipulated that Syria and Lebanon should agree a timetable for a complete Syrian pulllout. That is yet to be agreed.
Syria, which has 14,000 troops in Lebanon, pulled out or redeployed a few thousand troops last year. It was widely expected to pull out some more troops ahead of a general election in Lebanon, due to take place by May.
"Just as the Syrian regime must take stronger action to stop those who support violence and subversion in Iraq and must end its support for terrorist groups seeking to destroy the hope of peace between Israelis and Palestinians, Syria must also end its occupation of Lebanon," Bush said in a speech in Belgium.
Sami Baroudi, associate professor of political science at the Lebanese American University, said Bush's comments were part of the pressure on Syria to implement last year's UN Security Council resolution calling for it to quit Lebanon.
SYRIA OUT: Thousands of Lebanese protesters chanted "Syria out" as they marched in Beirut a week after Hariri's assassination.
Protesters carrying Lebanese flags and wearing red-and-white scarves, a symbol of the opposition, converged on an exclusive seafront area where the bomb tore through Hariri's motorcade.
They observed a one-minute silence at 12:55 pm (1055 GMT), the exact time Hariri was killed a week ago.
"The truth is, we can't stand Syria," protesters chanted, as well as "Syria out" and "Freedom, sovereignty, independence".
The protest was led by a number of mainly Christian and Druze opposition figures.