Prime Minister Ismail Haniyeh on Thursday instructed the Gaza-based Ministry of the Interior to "restore unity" among Palestinian factions in the field to protect the blockaded enclave.
In a meeting with security commanders, Haniyeh called on armed Palestinian factions to refrain from actions that could endanger Gaza, instructions interpreted as a call to join Hamas' two-year ceasefire with Israel.
The Gaza-based premier said his decision was an effort to prevent Israel from "taking advantage" of the pretext cited by its army for firing on Gaza following rocket attacks.
Haniyeh disputed Israel's rationale for an upsurge in attacks on the territory, saying they were intended "to overcome internal and political crises at the expense of the Palestinians."
At the meeting, he also met with security officials and briefed them on a conversation with Egyptian officials who had warned that Israel planned to attack the enclave if rocket attacks did not cease.
Late on Wednesday, Hamas officials had met with the main militant groups who had agreed to observe "national understanding" about a period of calm, and to avoid doing anything likely to provoke a strong Israeli reaction.
At the meeting, Hamas passed on a message from Egypt and other Arab leaders about the threat of a new Israeli operation in response to a rise in rocket fire from Gaza.
Earlier a Hamas minister told AFP the enclave's rulers would be sure to protect the calm.
"The national understanding among the factions means they won't give Israel any reason to make war on Gaza," he said, as Hamas security forces fanned out along the northern and eastern sectors of the border to enforce the truce.
"The government will protect this understanding because we don't want another tragedy to befall the Palestinian people," he said.
"Now Gaza is quieter than it has been since 2007 and Israel knows this."
The deployment of security personnel began overnight and continued Thursday, with witnesses and an AFP correspondent confirming Hamas had beefed up its forces along the border east of Gaza City, as well as to the north and were checking all cars on roads leading to the border.
In past weeks, Gaza militants have fired scores of rockets into Israel, prompting a flurry of retaliatory air strikes and raising fears of another massive operation along the lines of the 2008-9 war.
The 22-day war, which ended in a ceasefire on Jan. 18, 2009, killed 1,400 Palestinians, more than half of them civilians, and 13 Israelis, 10 of them soldiers.