The United States says it has received reports of possible plans to kidnap its nationals in the Gaza Strip.
By James Rodgers
BBC correspondent in Gaza
Americans are warned to be particularly cautious should they choose to travel to the territory.
US citizens might be targeted
Many western governments currently warn against travel to Gaza, the scene of fierce clashes during the last two-and-a-half years of the Israeli-Palestinian conflict.
Now kidnapping has been added to the list of potential dangers.
In a brief statement, the United States embassy in Tel Aviv says it has received credible reports of possible plans to kidnap US citizens in Gaza.
No further details are given.
The statement tells Americans to be particularly cautious.
It refers them to existing travel advice which says that US citizens in the West Bank and Gaza should consider moving to a safe location.
The only recent incident of foreigners in Gaza being held against their will turned out to be the work of a man who lost his job.
To highlight his disagreement with his former employers, he took a number of Europeans hostage.
They were released shortly afterwards.
This new warning from the United States suggests that there may be a more serious threat.