Tuesday night's successful Israel Defense Forces operation in Gaza thwarted a concrete and significant terror threat, but military officials admitted Wednesday that the tunnel attacked was only one of many threats which still exist in the Strip.

Defense Minister Ehud Barak held a special meeting with security officials Wednesday morning, and one of the issues discussed was the possibility of a complete collapse of the ceasefire between Israel and Hamas.

"Tonight's operation conveyed a message to Hamas that the IDF will not turn a blind eye when a tunnel is being dug near the fence," a military source said. "We proved that we know about it and do not hesitate to operate when needed."

The army has received information that before and throughout the truce, the terror organizations have been growing stronger and preparing for a conflict. Thus, defense sources estimate that Hamas has been working on terror attacks, which may be executed at any given time.

In the meeting with the defense minister, the officials also addressed the possibility of another escalation, as the rocket fire directed at western Negev communities and the city of Ashkelon continued.

The defense establishment has a line of action in such cases, ranging from a limited operation to wide-scale campaigns.

"It's hard to predict what will happen in the next 24 hours," said a security source. "In general, Hamas seeks to maintain the lull and is not likely to violate it anymore. Yet this is a terror organization which has been planning terror attacks in the past few months and may try and execute one of them."

Senior Israeli officials held talks with their Egyptian colleagues throughout the night and briefed them on the recent developments.

Deputy Defense Minister Matan Vilnai said at the end of the meeting, "We are not headed to an escalation. The lull brings peace and quiet to the southern communities, and we have an interest to maintain it."