The prosecutor in the Gaza military court on Saturday read the charges against the four: "possession of weapons and explosives, and placing explosive devices near Beit Lahia in the northern Gaza Strip with the intent of targetting Israeli tanks."
"It could be that the explosion that killed the Americans was caused by these devices," the prosecutor said.
On 15 October, three US security personnel working for the US embassy in Tel Aviv were killed in a roadside blast as a US diplomatic convoy travelled close to the Erez border crossing between Israel and the Gaza Strip.
No one has claimed responsibility for the blast, an unprecedented attack on a foreign target in the Palestinian territories.
Presiding judge Khalid Hamad almost immediately adjourned the hearing until 29 February, saying the defendants, who were arrested on the day of the attack, needed more time to select their attorneys.
The four accused - Naim Abu Ful, 42, Bashir Abu Laban, 41, Muhammad al-Dsuki Kamil Hamad, 22, and Ahmad Abd al-Fattah al-Safi, 23 - were all residents of the Jabaliya refugee camp in the Gaza Strip.
Hamad denied the charges against him, saying in court: "I have been unjustly imprisoned and I do not know why I am here."
The US State Department on Thursday placed advertisements in the Palestinian media offering a reward of up to $5 million for information leading to the arrest and indictment of anyone involved in the deadly attack.
Palestinian leader Yasir Arafat's national security advisor, Jibril al-Rajub, hit out at Washington on Wednesday, accusing it of "blackmailing" the Palestinians by halting its involvement in the Middle East peace process while awaiting the results of the investigation.
US State Department spokesman Richard Boucher rejected Rajub's claims as "ridiculous".