For a second day, a special U.N. envoy returned to a suburb of Damascus to investigate the suspected chemical weapons attack that killed hundreds of innocent civilians.

Heavily armed fighters accompanied the inspectors as they made their way to homes that were hit by last week's gas attack. After collecting more samples and interviewing survivors, the team returned to their hotel in Damascus.

As the investigation continues, U.N. Secretary-General Ban Ki-Moon says the inspectors need time.

SOUNDBITE: (English) UNITED NATIONS SECRETARY-GENERAL BAN KI-MOON, SAYING:

"Just days after the attacks, they have collected valuable samples and interviewed victims and witnesses. The team needs time to do its job."

Ban is in fact asking for four days to complete their mission -- and a U.N. official says there was friction with impatient Western governments ... likely to move forward with a military response even without U.N. approval.