Following a meeting with Palestinian leader Yasser Arafat in the West Bank town of Ramallah, former general Anthony Zinni said: "We need to end the violence and we need to get back on track towards peace".
Mr Arafat said the talks with Mr Zinni and US Assistant Secretary of State William Burns had been "intensive and important", adding he was "going to make [a] 100% effort" to achieve a ceasefire with Israel.
Washington has said Mr Zinni will stay in the region until he has secured a truce to end 14 months of violence and begin steps to revive peace talks between the two sides.
The discussions with the Palestinians came a day after Palestinian gunmen killed six Israelis and wounded scores of others in two separate attacks in the West Bank and Gaza, underscoring the challenge facing the envoys.
The US has said the Palestinians must not only denounce violence against Israel but put a stop to it.
Palestinian sources said Palestinian police had arrested 15 people connected to one of the groups involved in Tuesday's shooting in the northern Israeli city of Afula.
All belong to the Islamic Jihad group. No-one from the Al-Aqsa Brigades, which is linked to the Palestinian leader's Fatah faction and which also took part in the attack, has been arrested.
First-hand look
Before meeting Mr Arafat, the US entourage toured the West Bank by car, which, Mr Zinni said, gave him the chance "to see the difficulties presented to the Palestinians by the current situation".
The Palestinians have complained of suffering under a year-long Israeli blockade of Palestinian-controlled towns and villages on the West Bank.
Israel says it has set up roadblocks and checkpoints to try to stop Palestinian militants from infiltrating into Israel and carrying out attacks.
Removing the roadblocks is a key part of the Tenet agreement agreed to by Israel and the Palestinians last May but never implemented.
Each side is trying to convince the US mission the blame for the current violence lies squarely with the other.
On Tuesday, Israeli Prime Minister Ariel Sharon took the envoys on a helicopter tour of the West Bank for a first-hand look at what Israel regards as security concerns.
For their part, the Palestinians are expected to show General Zinni flashpoints in the West Bank and Gaza Strip in the coming days.