The first day of a controversial trial of 43 non-governmental organisation workers accused of working illegally and trying to push American and Israeli interests in Egypt has adjourned in Cairo.

The defendants include 19 Americans and 16 Egyptians, though only seven of the US citizens reportedly remain in the country, where they are prevented from leaving. The others include Serbs, Lebanese, Germans, a Norwegian, a Jordanian and a Palestinian.

Adjourning Sunday’s proceedings, Mohammed Shoukry, the chief judge, said the court will reconvene for the next hearing on April 26.

A prosecutor read the charges against the defendants, alleging that their acceptance of “illicit funds” had “detracted from the sovereignty of the Egyptian state”.

The 14 defendants who did appear, all Egyptians, denied that they had committed the crimes they were charged with.

The charging of the Americans has brought relations between Egypt and the United States to their lowest levels in three decades. US politicians have said they may cut off Egypt’s $1.3 billion in annual military aid if the US citizens are tried.

But on Sunday, none of the Americans appeared in court, according to media reports. Les Campbell, the regional director of one of the accused US organisations, said his group’s foreign employees did not receive official summons from the court, so they would not come.

The case involves five civil society groups that identify themselves as being pro-democracy, four of which are based in the United States.

A senior US official said on Saturday that the administration of Barack Obama, the US president, was in “intense discussions” with Egypt to resolve the legal case “in the coming days”.

Egyptian authorities have responded by blasting what they call US meddling in Egypt’s legal affairs.

Obama has urged Egypt’s military rulers to drop the investigation, and high-level officials, including Martin Dempsey, the joint chiefs chairman, and Republican Senator John McCain, have flown in to Cairo to seek a solution.

The US official, speaking to the Associated Press news agency on condition of anonymity due to the sensivity of the matter, said that Hillary Clinton, the secretary of state, had raised the matter twice in person with her Egyptian counterpart, Mohamed Amr, once, in London and once in Tunisia in the past three days.

On Sunday, Clinton said the US was “evaluating the outcomes” the day’s legal proceedings and that she would say more when that analysis had been completed.

The Americans work for the four US-based groups: the International Republican Institute, National Democratic Institute, International Center for Journalists and Freedom House. The groups have denied wrongdoing.

Sam LaHood, the son of Ray LaHood, the US transportation secretary, is among those not allowed to leave Egypt.

‘Illegal use of funds’

The activists have been charged with the illegal use of foreign funds to foment unrest and operating without a licence. But the investigation fits into a broader campaign by Egypt’s rulers against alleged foreign influence since the fall of Hosni Mubarak last year.

Rights groups have sharply criticised the investigation into the groups and the charges, saying they are part of an orchestrated effort by Egyptian authorities to silence groups critical of the military rulers.

“Of course this trial is politicised. We proved during the investigation that we didn’t do anything,” one of the defendants, Islam Shafiq, told AFP after the hearing. Shafiq works as a financial manager with the US-based International Centre

for Journalists,

Egyptian officials have said the trial has nothing to do with the government and is in the judiciary’s hands.

Egyptian officials have blamed continuing unrest in their country on foreign interference they attribute, in part, to the organisations.

Ashraf El-Ashmawi and Sameh Abu Zeid, the two judges handling the cases, said the charges could lead to five-year prison sentences.

“These organisations conducted unlicensed and illegal activities without the knowledge of the Egyptian government,” said El-Ashmawi. “Documents confiscated during the raids on the NGOs offices confirm illegal foreign funding.”

The state-run Al-Ahram daily reported that some of the computers seized in the raid in December 2011 had sensitive

information affecting Egypt’s national security.

The US state department says that seven of the 19 Americans facing trial have been barred from leaving Egypt by the country’s attorney general.