Heightened security checks will be carried out before Queens Park Rangers' FA Cup clash with Chelsea today after footballer Anton Ferdinand was allegedly sent a threatening package in the post.

The Metropolitan Police confirmed they are investigating a "malicious communication", which sources say was addressed to the Rangers defender who is currently at the centre of a high-profile race probe.

According to Sky News, the package, received by QPR yesterday, contained a bullet.

It is not known whether Ferdinand will take part in today's match in West London, though QPR has announced that "full searches" of all fans will be carried out before they enter the the club's home ground Loftus Road.

A Met Police spokesman refused to disclose the intended recipient of the package, but said: "I can confirm we are investigating an allegation of malicious communication received at QPR football club. Officers from Hammersmith and Fulham are investigating."

A statement released by QPR ahead of today's game said: "We would like to advise supporters from both QPR and Chelsea to arrive early at the stadium.

"Full searches will be carried out ahead of your entry to the ground, so please have your tickets to hand and be ready to be searched.

"Entry to the stadium will be permitted from 10.30am for the midday kick-off.

"We are asking for your full understanding and co-operation."

The fourth-round cup clash is expected to be the first time Ferdinand faces Chelsea captain John Terry since they became embroiled in a race-row during the team's last meeting at Loftus Road in October.

Terry has since been charged with racially abusing the QPR player and is expected to enter a not guilty plea at Westminster Magistrates' Court on Wednesday, having repeatedly denied the charge against him.

Ferdinand has reportedly spent £30,000 on personal security ahead of the London derby, but this has been played down by Rangers manager Mark Hughes.

Both clubs had issued strongly-worded statements this week warning supporters they faced arrest, ejection and stadium bans were they to engage in racist behaviour during the match.

Chelsea have vowed to ban anyone caught racially abusing Ferdinand from Stamford Bridge.